; *****************************************************************************************
; Copyright © [01/26/1999] Scenix Semiconductor, Inc. All rights reserved.
;
; Scenix Semiconductor, Inc. assumes no responsibility or liability for
; the use of this [product, application, software, any of these products].
; Scenix Semiconductor conveys no license, implicitly or otherwise, under
; any intellectual property rights.
; Information contained in this publication regarding (e.g.: application,
; implementation) and the like is intended through suggestion only and may
; be superseded by updates. Scenix Semiconductor makes no representation
; or warranties with respect to the accuracy or use of these information,
; or infringement of patents arising from such use or otherwise.
;*****************************************************************************************
; SX Single I2C Multi-Master demo.
;
; Filename: i2cmm.src
;
; Author: Chris Fogelklou and Bruce Wilson
; Applications Engineers
; Scenix Semiconductor Inc.
;
; Revision: 1.06b (preliminary, for review)
;
; Part: SX28AC datecode 9929AA
; Freq: 50Mhz
; Compiled using Parallax SXKey28L
; Parallax SXKey52
; SASM
;
; Date Written: Aug 23,1999
;
; Last Revised: June 26,2000
;
; Introduction:
; The I2C multi-master Virtual Peripheral™ has been written to enable the user to simply and
; easily operate the SX as an I2C master in multi-master mode. A multi-master I2C bus is when
; more than one master may initiate an I2C transfer on the I2C-bus. Arbitration is used to
; determine whether or not a master is able to use the bus at any given time.
;
; Program Description:
; This program is a very straight forward I2C multi-master demo, which uses the I2C multi-master
; VP as a foundation. This program relies on two aspects for correct multi-master operation. The
; first is an arbitration algorithm which executes every ISR. This arbitration algorithm is used to
; detect when a master may communicate on the bus, or if it must first wait for another master to
; finish. The second aspect which is important for correct operation of the I2C specification on
; the SX, is keeping a defined duration of the start-bit between masters. This ensures that a start
; may always be detected and that each SX master on the bus may synchronize their I2C clocks before
; beginning a transmission.
;
; To run this demo on the Scenix demo board all you need to do is ensure that the
; scl and sda pins, and that the slave address is set correctly. For pin and port setup, refer to
; the documentation for the demo board you are using (pdf-document)
; To read from the onboard EEPROM on the:
; The slave address for the EEPROM is $A0 for both the boards.
;
; If you run the programs in debug mode you will see the data contained in the EEPROM being read
; into the last RAM bank. You can also see the text read and the slave address beeing read from
; in a watch window. Your setup should be as follows:
;
; 4.7k
; VCC x--/\/\/\--------x
; 4.7k |
; VCC x--/\/\/\---x |
; | |
; | | SCL
; SCL ------------x------------------x-------- SCL
; SX 1 | SDA | SX 2
; SDA -----------------x-----------------x---- SDA
; | |
; | |
; SCL SDA
; EEPROM (24LC16B)
;
; The pin definitions on either SX can be easily changed. However, you are restricted to use pin
; 0 and 1 on the port you have assgned for I2C, but you are allowed to switch the SDA and SCL pins.
; It is also recommended that for testing purposes leds be connected to pins RC.0, RC.1 and RC.2. These can
; be used to verify correct operation of the multi-master system.
;
; Once both SX devices have been programmed they will read whatever data is stored in the first bank of the EEPROM
; until a null is found, this data will be written into bank 7 of the SX. Run in debug mode to see the data.
; Since each SX will be trying to do this at the same time, arbitration is used. The SX masters
; will wait until the bus is idle, or a start bit is being put onto the bus. In Either of these cases the master
; will begin transmission. Whichever master pulls the SDA line low first will now win the arbitration procedure.
; The master which loses arbitration will now wait a random length of time
; and then try again. This time that the master waits may need to be adjusted to suit your application. Since
; the way arbitration is detected is by the setting of a flag within the ISR, this allows the user to choose what
; action to take once loss of arbitration is detected. At present the master simply waits up to 85 I2C clock
; cycles before retrying the transmission. The length of this wait is totally dependant on the maximum length
; of any operation to take place on the I2C-bus. It would be unwise to have a timout period of as little as
; 50 clocks, if a master requires a 255 char string read from the EEPROM. It would be also possible to add more
; sophistication to the restart of a transmission whereby it may simply be continued from when arbitration was
; lost.
; Depending on the speed you wish to operate the I2C-bus at it may be necissary to change the pull-up resistor
; values. It is suggested that you refer to the I2C-bus specification pg. 40. This specificaiton is freely
; available at the Philips web site and has some good information on implementing the I2C specification.
;
; I2C Multi-Master VP requirements:
; - 1 RAM bank for I2C MultiMaster variables
; - 1 RAM bank for I2C MultiMaster string read from slave
; - 300 Bytes of Program memory
; - Up to 86 instruction cycles every ISR
;
; Interface Pins:
;
; i2cmmPort ra
; scl 1
; sda 0
;
; i2cmmGreenLed equ rc.2
; i2cmmRedLed2 equ rc.1
; i2cmmRedLed1 equ rc.0
;
;
; Revision History:
; 1.0 Core I2C state machine implemented by Chris Fogelklou
; 1.01 Documentation and code revised and updated by Bruce Wilson
; 1.02 Improved multi-master functionality and tested on the Scenix I2C/UART board
; 1.03 Modified code for SASM assembler and SX52 compatibility
; 1.04 Detection of NACK added to mainline code to avoid continuing a transmission even
; when the slave did not respond. This also solved a known bug, whereby loss of
; arbitration may sometimes not be detected due to timing between masters.
; 1.05 Added IFDEFs for SX28/52 and I2C/UART demo boards
; 1.06a Rewritten according to vp_guide_1_02.src, compabillity to SX48/52 and
; ISR cycle count. By Olav Gundersen
; 1.06b Added comments in program description, subroutines extended page moved to
; new page (PAGE4_ORG). By Olav Gundersen
;*****************************************************************************************
;*****************************************************************************************
; Target SX
; Uncomment one of the following lines to choose the SX18AC, SX20AC, SX28AC, SX48BD,
; or SX52BD.
;*****************************************************************************************
;SX18_20
SX28
;SX48_52
;*****************************************************************************************
; Assembler Used
; Uncomment the following line if using the Parallax SX-Key assembler. SASM assembler
; enabled by default.
;*****************************************************************************************
;SX_Key ; Uncomment this line to assemble this source code using the
; Parallax Assembler
;*********************************************************************************
; Assembler directives:
; high speed external osc, turbo mode, 8-level stack, and extended option reg.
;
; SX18/20/28 - 4 pages of program memory and 8 banks of RAM enabled by default.
; SX48/52 - 8 pages of program memory and 16 banks of RAM enabled by default.
;
;*********************************************************************************
IFDEF SX_Key ; SX-Key Directives
watch i2cmmRecvString,16,fstr ; Watch for simplify the debugging
watch i2cmmAddress,8,uhex ;
IFDEF SX18_20 ;SX18AC or SX20AC device directives for SX-Key
device SX18L,oschs2,turbo,stackx_optionx
ENDIF
IFDEF SX28 ;SX28AC device directives for SX-Key
device SX28L,oschs2,turbo,stackx_optionx
ENDIF
IFDEF SX48_52 ;SX48/52/BD device directives for SX-Key
device oschs2
ENDIF
freq 50_000_000
ELSE ;SASM Directives
IFDEF SX18_20 ;SX18AC or SX20AC device directives for SASM
device SX18,oschs2,turbo,stackx,optionx
ENDIF
IFDEF SX28 ;SX28AC device directives for SASM
device SX28,oschs2,turbo,stackx,optionx
ENDIF
IFDEF SX48_52 ;SX48BD or SX52BD device directives for SASM
device SX52,oschs2
ENDIF
ENDIF
multiMaster ; Enable the arbitration algorithm
id 'I2CMM' ; code identification
reset resetEntry ; set reset vector
;*****************************************************************************************
; Macros
;*****************************************************************************************
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
;
; To support compatibility between source code written for the SX28 and the SX52,
; use macros.
;
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
;*********************************************************************************
; Macro: _bank
; Sets the bank appropriately for all revisions of SX.
;
; This is required since the bank instruction has only a 3-bit operand, it cannot
; be used to access all 16 banks of the SX48/52. For this reason FSR.7 needs to be
; set appropriately, depending on the bank address being accessed. Use of this macro
; switches banks correctly, regardless of the part being compiled for.
;
; Instead of using the bank instruction to switch between banks, use _bank instead.
;
;*********************************************************************************
_bank macro 1 ;1,2
bank \1
IFDEF SX48_52
IF \1 & %10000000 ;SX48BD and SX52BD (production release) bank instruction
setb fsr.7 ;modifies FSR bits 4,5 and 6. FSR.7 needs to be set by software.
ELSE
clrb fsr.7
ENDIF
ENDIF
endm
;*****************************************************************************************
; Macros for SX28/52 Compatibility
;*****************************************************************************************
;*********************************************************************************
; Macro: _mode
; Sets the MODE register appropriately for all revisions of SX.
;
; This is required since the MODE (or MOV M,#) instruction has only a 4-bit operand.
; The SX18/20/28AC use only 4 bits of the MODE register, however the SX48/52BD have
; the added ability of reading or writing some of the MODE registers, and therefore use
; 5-bits of the MODE register. The MOV M,W instruction modifies all 8-bits of the
; MODE register, so this instruction must be used on the SX48/52BD to make sure the MODE
; register is written with the correct value. This macro fixes this.
;
; So, instead of using the MODE or MOV M,# instructions to load the M register, use
; _mode instead.
;
;*********************************************************************************
_mode macro 1
IFDEF SX48_52
expand
mov w,#\1 ;loads the M register correctly for the SX48BD and SX52BD
mov m,w
noexpand
ELSE
expand
mov m,#\1 ;loads the M register correctly for the SX18AC, SX20AC
noexpand ;and SX28AC
ENDIF
endm
;*****************************************************************************************
; INCP/DECP macros for incrementing/decrementing pointers to RAM
; used to compensate for incompatibilities between SX28 and SX52
;*****************************************************************************************
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
;
; To support compatibility between source code written for the SX28 and the SX52,
; use macros. This macro compensates for the fact that RAM banks are contiguous in
; the SX52, but separated by 0x20 in the SX18/28.
;
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
INCP macro 1
inc \1
IFNDEF SX48_52
setb \1.4 ; If SX18 or SX28, keep bit 4 of the pointer = 1
ENDIF ; to jump from $1f to $30, etc.
endm
DECP macro 1
IFDEF SX48_52
dec \1
ELSE
clrb \1.4 ; If SX18 or SX28, forces rollover to next bank
dec \1 ; if it rolls over. (Skips banks with bit 4 = 0)
setb \1.4 ; Eg: $30 --> $20 --> $1f --> $1f
ENDIF ; AND: $31 --> $21 --> $20 --> $30
endm
;*****************************************************************************************
; Error generating macros
; Used to generate an error message if the label is unintentionally moved into the
; second half of a page. Use for lookup tables.
;*****************************************************************************************
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
;
; Surround lookup tables with the tableStart and tableEnd macros. An error will
; be generated on assembly if the table crosses a page boundary.
;
; Example:
; lookupTable1
; add pc,w
; tableStart
; retw 0
; retw 20
; retw -20
; retw -40
; tableEnd
;
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
tableStart macro 0 ; Generates an error message if code that MUST be in
; the first half of a page is moved into the second half.
if $ & $100
ERROR 'Must be located in the first half of a page.'
endif
endm
tableEnd macro 0 ; Generates an error message if code that MUST be in
; the first half of a page is moved into the second half.
if $ & $100
ERROR 'Must be located in the first half of a page.'
endif
endm
;*****************************************************************************************
; Data Memory address definitions
; These definitions ensure the proper address is used for banks 0 - 7 for 2K SX devices
; (SX18/20/28) and 4K SX devices (SX48/52).
;*****************************************************************************************
IFDEF SX48_52
global_org = $0A
bank0_org = $00
bank1_org = $10
bank2_org = $20
bank3_org = $30
bank4_org = $40
bank5_org = $50
bank6_org = $60
bank7_org = $70
ELSE
global_org = $08
bank0_org = $10
bank1_org = $30
bank2_org = $50
bank3_org = $70
bank4_org = $90
bank5_org = $B0
bank6_org = $D0
bank7_org = $F0
ENDIF
;*****************************************************************************************
; Global Register definitions
; NOTE: Global data memory starts at $0A on SX48/52 and $08 on SX18/20/28.
;*****************************************************************************************
org global_org
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
;
; Use only these defined label types for global registers. If an extra temporary
; register is required, adhere to these label types. For instance, if two temporary
; registers are required for the Interrupt Service Routine, use the label isrTemp1
; for it.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
flags0 equ global_org + 0 ; stores bit-wise operators like flags
; and function-enabling bits (semaphores)
;VP: RS232 Receive
rs232RxFlag equ flags0.0 ;indicates the reception of a bit from the UART
flags1 equ global_org + 1 ; stores bit-wise operators like flags
; and function-enabling bits (semaphores)
localTemp0 equ global_org + 2 ; temporary storage register
; Used by first level of nesting
; Never guaranteed to maintain data
localTemp1 equ global_org + 3 ; temporary storage register
; Used by second level of nesting
; or when a routine needs more than one
; temporary global register.
localTemp2 equ global_org + 4 ; temporary storage register
; Used by third level of nesting or by
; main loop routines that need a loop
; counter, etc.
isrTemp0 equ global_org + 5 ; Interrupt Service Routine's temp register.
; Don't use this register in the mainline.
i2cRecvChar equ $0F ; received character from EEPROM
;*****************************************************************************************
; RAM Bank Register definitions
;*****************************************************************************************
;*********************************************************************************
; Bank 0
;*********************************************************************************
org bank0_org
bank0 = $
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; - Avoid using bank0 in programs written for SX48/52.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
;*********************************************************************************
; Bank 1
;*********************************************************************************
org bank1_org
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
;
; Tip 1:
; Indicate which Virtual Peripherals a portion of source code or declaration belongs
; to with a
; ";VP: VirtualPeripheralName"
; comment.
;
; Tip 2:
; All RAM location declaration names should be
; - left justified
; - less than 2 tabs in length
; - written in hungarian notation
; - prefixed by a truncated version of the Virtual Peripheral's name
;
; Examples:
;
; ;VP: RS232 Transmit
;
; rs232TxBank = $ ;RS232 Transmit bank
;
; rs232TxHigh ds 1 ;hi byte to transmit
; rs232TxLow ds 1 ;low byte to transmit
; rs232TxCount ds 1 ;number of bits sent
; rs232TxDivide ds 1 ;xmit timing (/16) counter
; rs232TxString ds 1 ;the address of the string to be sent
; rs232TxByte ds 1 ;semi-temporary serial register
;
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
;VP: ISR Multithreader
isrMultiplex ds 1 ; The isrMultiplex register is used to switch to a new
; execution thread on each pass of the ISR.
;VP_end
;VP_begin I2C Multi-Master
i2cmmBank = $ ; I2CM bank
i2cmmState ds 1 ; This indicates the state that the I2CM master is currently in.
i2cmmSubState ds 1 ; This indicates the substate that the I2C master is currently in.
i2cmmPortBuf ds 1 ; This buffer holds the current state of the I2C port direction reg's
i2cmmBitCount ds 1 ; Indicates the number of bits left to process in read/write
i2cmmByte ds 1 ; The byte currently being written/read by the I2C master
i2cmmFlags ds 1
i2cmmNack equ i2cmmFlags.0 ; This bit is set if the I2C master has received a NACK from the slave
i2cmmRxFlag equ i2cmmFlags.1 ; Indicates that the number of bytes requested have been received
i2cmmLostArb equ i2cmmFlags.2 ; indicates that this master has lost arbitration
i2cmmDoingWrite equ i2cmmFlags.4 ; Used to remember whether doing a read or write when recovering from loss of arbitration
i2cmmInControl equ i2cmmFlags.5 ; Indicates that this master thinks it is in control of the I2C bus
i2cmmIndex ds 1 ; The index into the I2CM buffer, used for writing
i2cmmNumBytes ds 1 ; The index into the I2CM buffer, used for reading
i2cmmStrtCtr ds 1 ; Counts the number of SCL high cycles before sending a start bit onto the i2c-bus
i2cmmBuffer = $ ; The buffer uses the last 7 registers of this bank (pre-increments, so put I2CM buffer here.)
i2cmmAddress ds 1 ; The address to read/write to.
i2cmmDataBuf ds 6 ; Data buffer
; These data registers could easily be placed into another bank if more data memory is required
;VP_end ; End cut/paste for I2C MultiMaster
;*********************************************************************************
; Bank 2
;*********************************************************************************
org bank2_org
bank2 = $
;VP_begin I2C Multi-Master
i2cmmTimer = $
i2cmmTimerLow ds 1
i2cmmTimerHigh ds 1
VARS = $
i2cmmWritePtr ds 1 ; points to where data can be written
i2cmmReadAdr ds 1 ; used to point to address of slave to read
;VP_end ; End cut/paste for I2C MultiMaster
;*********************************************************************************
; Bank 3
;*********************************************************************************
org bank3_org
bank3 = $
;*********************************************************************************
; Bank 4
;*********************************************************************************
org bank4_org
bank4 = $
;*********************************************************************************
; Bank 5
;*********************************************************************************
org bank5_org
bank5 = $
;*********************************************************************************
; Bank 6
;*********************************************************************************
org bank6_org
bank6 = $
;*********************************************************************************
; Bank 7
;*********************************************************************************
org bank7_org
bank7 = $
;VP_begin I2C Multi-Master
i2cmmRecvString = $ ; where a string can be stored
;VP_end ; End cut/paste for I2C MultiMaster
IFDEF SX48_52
;*********************************************************************************
; Bank 8
;*********************************************************************************
org $80 ;bank 8 address on SX52
bank8 = $
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; - This extra memory is not available in the SX18/28, so don't use it for Virtual
; Peripherals written for both platforms.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
;*********************************************************************************
; Bank 9
;*********************************************************************************
org $90 ;bank 9 address on SX52
bank9 = $
;*********************************************************************************
; Bank A
;*********************************************************************************
org $A0 ;bank A address on SX52
bankA = $
;*********************************************************************************
; Bank B
;*********************************************************************************
org $B0 ;bank B address on SX52
bankB = $
;*********************************************************************************
; Bank C
;*********************************************************************************
org $C0 ;bank C address on SX52
bankC = $
;*********************************************************************************
; Bank D
;*********************************************************************************
org $D0 ;bank D address on SX52
bankD = $
;*********************************************************************************
; Bank E
;*********************************************************************************
org $E0 ;bank E address on SX52
bankE = $
;*********************************************************************************
; Bank F
;*********************************************************************************
org $F0 ;bank F address on SX52
bankF = $
ENDIF
;*********************************************************************************
; Pin Definitions:
;*********************************************************************************
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; - Store all initialization constants for the I/O in the same area, so
; pins can be easily moved around.
; - Pin definitions should follow the same format guidelines as RAM definitions
; - Left justified
; - Hungarian Notation
; - Less that 2 tabs in length
; - Indicate the Virtual Peripheral the pin is used for
; - Only use symbolic names to access a pin/port in the source code.
; - Example:
; ; VP: RS232 Transmit
; rs232TxPin equ ra.3
;
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
RA_latch equ %11111111 ;SX18/20/28/48/52 port A latch init
RA_DDIR equ %11111111 ;SX18/20/28/48/52 port A DDIR value
RA_LVL equ %11111111 ;SX18/20/28/48/52 port A LVL value, set to CMOS
RA_PLP equ %00000000 ;SX18/20/28/48/52 port A PLP value, set to pull-up
;VP_begin I2C Multi-Master
i2cmmPort equ ra
scl equ 1
sda equ 0
i2cmmSclPin equ i2cmmPort.scl ; I2C clock
i2cmmSdaPin equ i2cmmPort.sda ; I2C data I/O
;VP_end ; End cut/paste for I2C MultiMaster
RB_latch equ %11111111 ;SX18/20/28/48/52 port B latch init
RB_DDIR equ %11111111 ;SX18/20/28/48/52 port B DDIR value
RB_ST equ %11111111 ;SX18/20/28/48/52 port B ST value
RB_LVL equ %00000000 ;SX18/20/28/48/52 port B LVL value
RB_PLP equ %00000000 ;SX18/20/28/48/52 port B PLP value
RC_latch equ %11111111 ;SX18/20/28/48/52 port C latch init
RC_DDIR equ %11111000 ;SX18/20/28/48/52 port C DDIR value, set to out on RC.0-2
RC_ST equ %11111111 ;SX18/20/28/48/52 port C ST value
RC_LVL equ %11111111 ;SX18/20/28/48/52 port C LVL value
RC_PLP equ %00000000 ;SX18/20/28/48/52 port C PLP value
;VP_begin I2C Multi-Master
i2cmmGreenLed equ rc.2
i2cmmRedLed2 equ rc.1
i2cmmRedLed1 equ rc.0
;VP_end ; End cut/paste for I2C MultiMaster
IFDEF SX48_52 ;SX48BD/52BD Port initialization values
RD_latch equ %00000000 ;SX48/52 port D latch init
RD_DDIR equ %11111111 ;SX48/52 port D DDIR value
RD_ST equ %11111111 ;SX48/52 port D ST value
RD_LVL equ %00000000 ;SX48/52 port D LVL value
RD_PLP equ %00000000 ;SX48/52 port D PLP value
RE_latch equ %00000000 ;SX48/52 port E latch init
RE_DDIR equ %11111111 ;SX48/52 port E DDIR value
RE_ST equ %11111111 ;SX48/52 port E ST value
RE_LVL equ %00000000 ;SX48/52 port E LVL value
RE_PLP equ %00000000 ;SX48/52 port E PLP value
ENDIF
;*****************************************************************************************
; Program constants
;*****************************************************************************************
;-------------------------------------------------------------------------------------
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; To calculate the interrupt period in cycles:
; - First, choose the desired interrupt frequency
; - Should be a multiple of each Virtual Peripherals sampling frequency.
; - Example: 19200kHz UART sampling rate * 16 = 307.200kHz
; - Next, choose the desired oscillator frequency.
; - 50MHz, for example.
; - Perform the calculation intPeriod = (osc. frequency / interrupt frequency)
; = (50MHz / 307.2kHz)
; = 162.7604
; - Round intPeriod to the nearest integer:
; = 163
; - Now calculate your actual interrupt rate:
; = osc. frequency / intPeriod
; = 50MHz / 163
; = 306.748kHz
; - This interrupt frequency will be the timebase for all of the Virtual
; Peripherals
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
intPeriod = 86 ; Gives an interrupt period at 50MHz of (86 * (1/50000000)s) = 1.76us
; Which gives an interrupt frequency of (1/1.76us)Hz = 581.395kHz
; This is the double of the I2C bus frequency.
; intPeriod = clk_speed/(2x3 x bus_speed)
; e.g this intPeriod gives us a bus of:
; busSpeed= 50Mhz/(2 x 3 x intPeriod)= 96.9kHz
;VP_begin I2C Multi-Master
i2cmmSlaveAddr = $a0
;VP_end ; End cut/paste for I2C MultiMaster
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; - Include all calculations for Virtual Peripheral constants for any sample
; rate.
; - Relate all Virtual Peripheral constants to the sample rate of the Virtual
; Peripheral.
; - Example:
; ; VP: 5ms Timer
; TIMER_DIV_CONST equ 192 ; This constant = timer sample rate/200Hz = 192
;
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
;-------------------------------------------------------------------------------------
IFDEF SX48_52
;*********************************************************************************
; SX48BD/52BD Mode addresses
; *On SX48BD/52BD, most registers addressed via mode are read and write, with the
; exception of CMP and WKPND which do an exchange with W.
;*********************************************************************************
; Timer (read) addresses
TCPL_R equ $00 ;Read Timer Capture register low byte
TCPH_R equ $01 ;Read Timer Capture register high byte
TR2CML_R equ $02 ;Read Timer R2 low byte
TR2CMH_R equ $03 ;Read Timer R2 high byte
TR1CML_R equ $04 ;Read Timer R1 low byte
TR1CMH_R equ $05 ;Read Timer R1 high byte
TCNTB_R equ $06 ;Read Timer control register B
TCNTA_R equ $07 ;Read Timer control register A
; Exchange addresses
CMP equ $08 ;Exchange Comparator enable/status register with W
WKPND equ $09 ;Exchange MIWU/RB Interrupts pending with W
; Port setup (read) addresses
WKED_R equ $0A ;Read MIWU/RB Interrupt edge setup, 0 = falling, 1 = rising
WKEN_R equ $0B ;Read MIWU/RB Interrupt edge setup, 0 = enabled, 1 = disabled
ST_R equ $0C ;Read Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
LVL_R equ $0D ;Read Port Level setup, 0 = CMOS, 1 = TTL
PLP_R equ $0E ;Read Port Weak Pullup setup, 0 = enabled, 1 = disabled
DDIR_R equ $0F ;Read Port Direction
; Timer (write) addresses
TR2CML_W equ $12 ;Write Timer R2 low byte
TR2CMH_W equ $13 ;Write Timer R2 high byte
TR1CML_W equ $14 ;Write Timer R1 low byte
TR1CMH_W equ $15 ;Write Timer R1 high byte
TCNTB_W equ $16 ;Write Timer control register B
TCNTA_W equ $17 ;Write Timer control register A
; Port setup (write) addresses
WKED_W equ $1A ;Write MIWU/RB Interrupt edge setup, 0 = falling, 1 = rising
WKEN_W equ $1B ;Write MIWU/RB Interrupt edge setup, 0 = enabled, 1 = disabled
ST_W equ $1C ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
LVL_W equ $1D ;Write Port Level setup, 0 = CMOS, 1 = TTL
PLP_W equ $1E ;Write Port Weak Pullup setup, 0 = enabled, 1 = disabled
DDIR_W equ $1F ;Write Port Direction
ELSE
;*********************************************************************************
; SX18AC/20AC/28AC Mode addresses
; *On SX18/20/28, all registers addressed via mode are write only, with the exception of
; CMP and WKPND which do an exchange with W.
;*********************************************************************************
; Exchange addresses
CMP equ $08 ;Exchange Comparator enable/status register with W
WKPND equ $09 ;Exchange MIWU/RB Interrupts pending with W
; Port setup (read) addresses
WKED_W equ $0A ;Write MIWU/RB Interrupt edge setup, 0 = falling, 1 = rising
WKEN_W equ $0B ;Write MIWU/RB Interrupt edge setup, 0 = enabled, 1 = disabled
ST_W equ $0C ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
LVL_W equ $0D ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
PLP_W equ $0E ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
DDIR_W equ $0F ;Write Port Direction
ENDIF
;VP_begin I2C Multi-Master
i2cmmStrtDelay = 4 ; This start delay is critical in the operation
; of the multi-master system. The value of i2cmmStrtDelay
; specifies the number of ISR's that the scl line must
; be held high for before a start bit will be sent.
; If all masters on the I2C bus are running at the same clock speed, simply leave the value set
; at 4. If for example one of the masters is running twice as fast as another then this value may
; need to be changed. A good rule of thumb is the slowest master must have a delay of at least 4 and the
; faster masters use multiples of that relative to their clock speeds. The principle of this is
; simply to keep the length of the start bit the same no matter which master is using the bus. This
; makes it easy to detect and know when it is okay to use the bus. The other reason for changing this
; value is to change the relative amount of time that each master will be allocated.
; eg. run SX 1 with intPeriod = 166 (100kHz) and i2cmmStrtDelay = 4
; SX 2 with intPeriod = 111 (150kHz) and i2cmmStrtDelay = 6
; Running at 100kHz with 50Mhz clock, a i2cmmStrtDelay of 3 gives a start+stop pulse of approx. 24us
; The higher the delay the less timing critical arbitration will be. For instance if the i2cmmStrtDelay is
; 3 this will work fine only as long as other masters are running at the same frequency. But if you
; increase the value to 4 you will find that operation will still continue fine even with a difference
; of 50kHz, as in the example settings above.
; If you are not running this master in multi-master mode it is possible to decrease the start_delay
; to 1, this improves data throughput by reducing the width of the start+stop pulse to 17us.
IFNDEF multiMaster
i2cmmStrtDelay = 1
ENDIF
;VP_end ; End cut/paste for I2C MultiMaster
;*****************************************************************************************
; Program memory ORG defines
;*****************************************************************************************
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; - Place a table at the top of the source with the starting addresses of all of
; the components of the program.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
INTERRUPT_ORG equ $0 ; Interrupt must always start at location zero
RESET_ENTRY_ORG equ $1FB ; The program will jump here on reset.
SUBROUTINES_ORG equ $200 ; The subroutines are in this location
STRINGS_ORG equ $300 ; The strings are in location $300
PAGE3_ORG equ $400 ; Page 3 is empty
PAGE4_ORG equ $500 ; Additional subroutines for I2CMM
MAIN_PROGRAM_ORG equ $600 ; The main program is in the last page of program memory.
;****************************** Beginning of program space *******************************
;*****************************************************************************************
;*****************************************************************************************
;*****************************************************************************************
org INTERRUPT_ORG ; First location in program memory.
;*****************************************************************************************
;------------------------------------------------------------------------------
; Interrupt Service Routine
;------------------------------------------------------------------------------
; Note: The interrupt code must always originate at address $0.
;
; Interrupt Frequency = (Cycle Frequency / -(retiw value)) For example:
; With a retiw value of -163 and an oscillator frequency of 50MHz, this
; code runs every 3.26us.
;------------------------------------------------------------------------------
ISR ;3 The interrupt service routine...
;------------------------------------------------------------------------------
;VP: VP Multitasker
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; - Multi-thread the Interrupt Service Routine
; - Produces a FAR smaller worst-case cycle time count, and enables a larger number
; of VP's to run simultaneously. Also produces "empty" slots that future VP's
; can be copied and pasted into easily.
; - Determine how often your tasks need to run. (9600bps UART can run well at a
; sampling rate of only 38400Hz, so don't run it faster than this.)
; - Strategically place each "module" into the threads of the ISR. If a module
; must be run more often, just call it's module at double the rate or quadruple
; the rate, etc.…
; - Split complicated Virtual Peripherals into several modules, keeping the
; high-speed portions of the Virtual Peripherals as small and quick as possible,
; and run the more complicated, slower processing part of the Virtual Peripheral
; at a lower rate.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
;------------------------------------------------------------------------------
; Virtual Peripheral Multitasker: up to 24 individual threads, each running at
; the interrupt rate/24. Change the number of
; table entries for each thread to change the
; sample rate of that thread.
;
; Input variable(s): isrMultiplex: variable used to choose threads
; Output variable(s): None, executes the next thread
; Variable(s) affected: isrMultiplex
; Flag(s) affected: None
; Program Cycles: 9 cycles (turbo mode SX28)
;------------------------------------------------------------------------------
_bank isrMultiplex ;1 (or 2 in SX52)
inc isrMultiplex ;1 ; toggle interrupt rates
mov w,isrMultiplex ;1
; The code between the tableBegin and tableEnd statements MUST be
; completely within the first half of a page. The routines
; it is jumping to must be in the same page as this table.
tableStart ; Start all tables with this macro.
add pc,w ;3
jmp isrThread1 ;3 = 9/10 + 52/76 = 61/86 cycles
jmp isrThread2 ;
jmp isrThread1 ;
jmp isrThread3 ;
jmp isrThread1 ;
jmp isrThread4 ;
jmp isrThread1 ;
jmp isrThread5 ;
jmp isrThread1 ;
jmp isrThread2 ;
jmp isrThread1 ;
jmp isrThread6 ;
jmp isrThread1 ;
jmp isrThread7 ;
jmp isrThread1 ;
jmp isrThread3 ;
jmp isrThread1 ;
jmp isrThread2 ;
jmp isrThread1 ;
jmp isrThread8 ;
jmp isrThread1 ;
jmp isrThread9 ;
jmp isrThread1 ;
jmp isrThread16 ;
tableEnd ; End all tables with this macro.
;------------------------------------------------------------------------------
;VP: VP Multitasker
; ISR TASKS
;------------------------------------------------------------------------------
isrThread1 ; Serviced at ISR rate / 2
;------------------------------------------------------------------------------
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; The sample rate of this section of code is the isr rate / 2, because it is jumped
; to in every 2nd entry in the VP Multitaskers table. To increase the
; sample rate, put more calls to this thread in the Multitasker's jump table.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
;VP_begin I2C Multi-Master
;*********************************************************************************
; Keep running 8bit timer...
; Uncomment the two lines below if a 16 bit timer is needed (be aware that this
; adds two cycles to this ISR thread).
;*********************************************************************************
_bank i2cmmTimer ;1 (or 2 in SX48/52)
inc i2cmmTimerLow ;1
; snz ;1
; inc i2cmmTimerHigh ;1
;= 2/3 + 9 = 11/12
;*********************************************************************************
; I2C Master Virtual Peripheral
;*********************************************************************************
_bank i2cmmBank ;1 (or 2 in SX52)
mov w,#i2cmmBuffer ;1 ; Switch to I2CM bank and load FSR for
mov fsr,w ;1 ; buffer look-up, if needed.
call @i2cmmISR ;3 + i2cmmISR = 17/18 + 12/26 =
; = 29/44
;*********************************************************************************
; Update I2C port with buffered port data
;*********************************************************************************
mov w,m ;1 ; Save the m register.
mov isrTemp0,w ;1
_mode DDIR_W ;1 (2 for 48/52
mov w,i2cmmPort ;1
and w,#%11110000 ;1 ; Clear the data latches for SCL and SDA
mov i2cmmPort,w ;1
_bank i2cmmBank ;1 (or 2 in SX52)
mov w,i2cmmPortBuf ;1
mov !i2cmmPort,w ;1 ; Update the I2C port with the buffered port data
mov w,isrTemp0 ;1 ; Restore the m register.
mov m,w ;1
;= 11/13 + 29/44 = 40/57
;*********************************************************************************
; i2cmmArbitration
; This code checks to see that the data written by I2CM is the same
; as the data present on the bus. If not, this master has lost arbitration.
;*********************************************************************************
IFDEF multiMaster
i2cmmArb
_bank i2cmmBank ;1 (or 2 in SX52)
; --- Check if arbitration required ---
snb i2cmmLostArb ;1 ; No need to check if lost arb. already lost
jmp i2cmmArbDone ;3
sb i2cmmInControl ;1 ; Only check arbitration when master is in control
jmp i2cmmArbDone ;3
; --- Check if data on bus matches data written by master ---
snb i2cmmSdaPin ;1 ; No master can have lost arb. when sda is high
jmp i2cmmArbDone ;3
sb i2cmmPortBuf.sda ;1 ; check if buffer wants data high, if it does master loses arb.
jmp i2cmmArbDone ;3
; --- Arbitration has been lost. The master must now wait a 'random' time before trying again ---
:i2cmmArbLost setb i2cmmLostArb ;1 ; signal a loss of arbitration (just lost)
clr i2cmmState ;1 ; Put state machine into IDLE state
clr i2cmmSubState ;1
i2cmmArbDone ; = 5/12 + 40/57 = 45/69
ENDIF
;VP_end ; End cut/paste for I2C MultiMaster
jmp isrOut ;7 cycles until mainline program resumes execution
; = 7 + 45/69 = 52/76
;------------------------------------------------------------------------------
isrThread2 ; Serviced at ISR rate / 8
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread3 ; Serviced at ISR rate / 12
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread4 ; Serviced at ISR rate / 24
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread5 ; Serviced at ISR rate / 24
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread6 ; Serviced at ISR rate / 24
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread7 ; Serviced at ISR rate / 24
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread8 ; Serviced at ISR rate / 24
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread9 ; Serviced at ISR rate / 24
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread10 ; Never serviced
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread11 ; Never serviced
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread12 ; Never serviced
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread13 ; Never serviced
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread14 ; Never serviced
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread15 ; Never serviced
;------------------------------------------------------------------------------
jmp isrOut ;7 cycles until mainline program resumes execution
;------------------------------------------------------------------------------
isrThread16 ; Serviced at ISR rate / 24
; ; This thread must reload the isrMultiplex register
; since it is the last one to run in a rotation.
;------------------------------------------------------------------------------
_bank isrMultiplex
mov w,#255 ; Reload isrMultiplex so isrThread1 will be run
mov isrMultiplex,w ; on next interrupt.
jmp isrOut
;------------------------------------------------------------------------------
;------------------------------------------------------------------------------
isrOut
;------------------------------------------------------------------------------
mov w,#-intPeriod ;1 ; return and add -intPeriod to the RTCC
retiw ;3 ; using the retiw instruction.
;------------------------------------------------------------------------------
;*****************************************************************************************
org RESET_ENTRY_ORG
;*****************************************************************************************
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; The main program operation should be easy to find, so place it at the end of the
; program code. This means that if the first page is used for anything other than
; main program source code, a reset_entry must be placed in the first page, along
; with a 'page' instruction and a 'jump' instruction to the beginning of the
; main program.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
;------------------------------------------------------------------------------
resetEntry ; Program starts here on power-up
page _resetEntry
jmp _resetEntry
;------------------------------------------------------------------------------
;*****************************************************************************************
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; ORG statements should use predefined labels rather than literal values.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
org SUBROUTINES_ORG
;*****************************************************************************************
; Subroutines
;*****************************************************************************************
;VP_begin I2C Multi-Master
;*****************************************************************************************
; I2C Master Interrupt Service Routines
;*****************************************************************************************
; I2C Virtual Peripheral...
;*********************************************************************************
; Function: i2cmmISR
; I2C Master Interrupt-Driven State Machine
; -------------------------------------------
; This is the I2C Master Interrupt Service Routine. It is an interrupt-
; driven state machine which allows all of the actions of the I2C Master
; controller to be carried out, virtual peripheral style, with virtually
; no interaction from the mainline program.
; i2cmmIdle
; This is the state that the I2C Master is usually in when it is not in use.
; It just ensures that the I2C_port_buf SCL and SDA are both set high
; i2cmmStart
; When any mainline program wants to use the I2C master it puts the master into
; start mode. This mode creates a start condition on the I2C bus. A start
; condition is created when SDA goes from high to low while SCL stays high.
; i2cmmStartWrite
; This state performs some pre-processing which allows the i2cmmWrite state to
; do its work. It sets up the bit count, gets the next piece of data from the
; buffer and prepares to send it.
; i2cmmWrite
; This state writes the data in i2cmmByte to the I2C bus
; i2cmmGetAck
; This state gets an ACK from the slave device. If no ACK is received, the I2C
; Master state machine puts a stop condition on the bus and the i2cmmFlags
; register is loaded to indicate that a NACK has occurred.
; i2cmmWriteRepeat
; This state determines, after one byte of data is sent, whether or not
; there is another byte to be sent. If so, this state goes back to i2cmmStartWrite
; and sends the next byte.
; i2cmmStop
; This state puts a stop condition on the I2C bus and resets the state machine back
; to its idle state. A stop condition is when SDA goes from low to high while SCL
; is high.
; i2cmmStartRead
; This state simply loads the contents of the i2cmmAddress register into the i2cmmByte
; register and sets up the i2cmmWrite state to output the address of the slave to read.
; i2cmmReadData
; This state prepares the I2CM read routine so it can read from the slave device. It
; initializes the bit count, etc.
; i2cmmRead
; This state read 8 bits of data from the slave device.
; i2cmmStoreByte
; This state stores the byte just read into the buffer.
; i2cmmSendAck
; This state sends an ack if there is data left to write, and a NACK if there is
; no data left to write.
;*********************************************************************************
i2cmmISR
mov w,i2cmmState ;1
; The code between the tableStart and tableEnd statements
; MUST be completely within the first half of a page. The routines
tableStart ; it is jumping to must be in the same page as this table.
add PC,w ;3 ;Add the state to the program counter
;and go to the state in the jump table.
;*************************************************************************
; States for I2C Master while idle
;*************************************************************************
i2cmmIdleLoc = $
jmp i2cmmIdle ;3 ;If I2C_state = 0, I2C is idle
;*************************************************************************
; States for I2C Master while writing
;*************************************************************************
i2cmmWriteLoc = $
jmp i2cmmStart ;3 ;Make SDA go low while SCL is high
jmp i2cmmStartWrite ;3 ;Load a byte from the buffer and prepare to send.
jmp i2cmmWrite ;3 ;Write it.
jmp i2cmmGetAck ;3 ;Get an ACK signal
jmp i2cmmWriteRepeat ;3 ;Check to see if we have finished sending
;(if buffer read index = buffer write index)
i2cmmStopLoc = $
jmp i2cmmStop ;3 ;If write_repeat determines we're finished,
;then send stop
;*************************************************************************
; States for I2C Master while reading
;*************************************************************************
i2cmmReadLoc = $ ;Load this state into state machine if we
;are starting to read
jmp i2cmmStart ;3 ;
jmp i2cmmStartRead ;3 ;Write address used for reading
jmp i2cmmWrite ;3 ;(writing address)
jmp i2cmmGetAck ;3 ;
i2cmmReadRptLoc = $
jmp i2cmmReadData ;3 ;
jmp i2cmmRead ;3 ;Keep doing this until done
jmp i2cmmStoreByte ;3 ;
jmp i2cmmSendAck ;3 ;
jmp i2cmmStop ;3 ;
tableEnd ; = 7 (from i2cmmISR to here)
;*********************************************************************************
; State: i2cmmIdle
; This is the state that the I2C Master is usually in when it is not in use.
; It just ensures that the I2C_port_buf SCL and SDA are both set high
;*********************************************************************************
i2cmmIdle setb i2cmmPortBuf.sda ;1
setb i2cmmPortBuf.scl ;1
retp ;3 = 5 + 7 = 12
;*********************************************************************************
; State: i2cmmStart
; When any mainline program wants to use the I2C master it puts the master into
; start mode. This mode creates a start condition on the I2C bus. A start
; condition is created when SDA goes from high to low while SCL stays high.
;*********************************************************************************
i2cmmStart mov w,i2cmmSubState ;1
; The code between the tableStart and tableEnd statements
; MUST be completely within the first half of a page. The routines
tableStart ; it is jumping to must be in the same page as this table.
add pc,w ;3
jmp :state1 ;3
jmp :state2 ;3
jmp :state3 ;3
jmp :state4 ;3
jmp :state5 ;3 = 7 + 7 = 14
tableEnd
:state1 setb i2cmmPortBuf.scl ;1
setb i2cmmInControl ;1
setb i2cmmPortBuf.sda ;1
inc i2cmmSubState ;1
mov w,#i2cmmStrtDelay ;1
mov i2cmmStrtCtr,w ;1
retp ;3 = 9 + 14 = 23
; --- WAITING FOR STOP/START OR IDLE SCL ---
:state2 sb i2cmmSclPin ;1
clr i2cmmSubState ;1
decsz i2cmmStrtCtr ;1
retp ;3 = 6 + 14 = 20
inc i2cmmSubState ;1
retp ;3 = 8 + 14 = 22
; --- FINISHED CLOCK SYNCRONIZATION PERIOD ---
:state3 clrb i2cmmPortBuf.sda ;1
inc i2cmmSubState ;1
retp ;3 = 5 + 14 = 19
:state4 clrb i2cmmPortBuf.scl ;1
inc i2cmmSubState ;1
retp ;3 = 5 + 14 = 19
:state5 setb i2cmmPortBuf.sda ;1
clr i2cmmSubState ;1
inc i2cmmState ;1
retp ;3 = 6 + 14 = 20
;*********************************************************************************
; State: i2cmmStartWrite
; This state performs some pre-processing which allows the i2cmmWrite state to
; do its work. It sets up the bit count, gets the next piece of data from the
; buffer and prepares to send it.
;*********************************************************************************
i2cmmStartWrite
inc i2cmmIndex ;1
mov w,i2cmmIndex ;1
add fsr,w ;1
mov w,indf ;1
mov i2cmmByte,w ;1
mov w,#8 ;1
mov i2cmmBitCount,w ;1
inc i2cmmState ;1
retp ;3 = 11 + 7 = 18
;*********************************************************************************
; State: i2cmmWrite
; This state writes the data in i2cmmByte to the I2C bus
;*********************************************************************************
i2cmmWrite mov w,i2cmmSubState ;1
; The code between the tableStart and tableEnd statements
; MUST be completely within the first half of a page. The routines
tableStart ; it is jumping to must be in the same page as this table.
add pc,w ;3
jmp :state1 ;3
jmp :state2 ;3
jmp :state3 ;3 = 7 + 7 = 14
tableEnd
:state1 setb i2cmmInControl ;1
setb i2cmmPortBuf.sda ;1
rl i2cmmByte ;1
sb c ;1
clrb i2cmmPortBuf.sda ;1
inc i2cmmSubState ;1
retp ;3 = 9 + 14 = 23
:state2 setb i2cmmPortBuf.scl ;1
inc i2cmmSubState ;1
retp ;3 = 5 + 14 = 19
:state3 clrb i2cmmPortBuf.scl ;1
dec i2cmmBitCount ;1
snb z ;1
jmp :done ;3
clr i2cmmSubState ;1
retp ;3 = 8 + 14 = 22
:done clr i2cmmSubState ;1
inc i2cmmState ;1
clrb i2cmmInControl ;1
retp ;3 = 12 + 14 = 26
;*********************************************************************************
; State: i2cmmGetAck
; This state gets an ACK from the slave device. If no ACK is received, the I2C
; Master state machine puts a stop condition on the bus and the i2cmmFlags
; register is loaded to indicate that a NACK has occurred.
;*********************************************************************************
i2cmmGetAck mov w,i2cmmSubState ;1
; The code between the tableStart and tableEnd statements
; MUST be completely within the first half of a page. The routines
tableStart ; it is jumping to must be in the same page as this table.
add pc,w ;3
jmp :state1 ;3
jmp :state2 ;3
jmp :state3 ;3
jmp :state4 ;3 = 7 + 7 = 14
tableEnd
:state1 setb i2cmmPortBuf.sda ;1
inc i2cmmSubState ;1
retp ;3 = 5 + 14 = 19
:state2 setb i2cmmPortBuf.scl ;1
inc i2cmmSubState ;1
retp ;3 = 5 + 14 = 19
:state3 sb i2cmmSdaPin ;1
inc i2cmmSubState ;1
sb i2cmmSdaPin ;1
retp ;3 = 6 + 14 = 20 ;if ack,
mov w,#(i2cmmStopLoc-i2cmmIdleLoc);1
mov i2cmmState,w ;1
clr i2cmmSubState ;1 ;send a stop and indicate that this didn't work.
setb i2cmmNack ;1 ;set i2cmmNack to show that this did not go through.
retp ;3 = 11 + 14 = 25
:state4 clrb i2cmmPortBuf.scl ;1
clr i2cmmSubState ;1
inc i2cmmState ;1 ;move on to next state
retp ;3 = 6 + 14 = 20
;*********************************************************************************
; State: i2cmmWriteRepeat
; This state determines, after one byte of data is sent, whether or not
; there is another byte to be sent. If so, this state goes back to
; i2cmmStartWrite and sends the next byte.
;*********************************************************************************
i2cmmWriteRepeat
mov w,i2cmmNumBytes ;1 ;test the read index to see if it is = to write index.
xor w,i2cmmIndex ;1 ;if it is, then we have finished writing the buffer via. I2C.
snb z ;1
jmp :i2cmmWriteDone ;3
dec i2cmmState ;1 ;back to GetAck
dec i2cmmState ;1 ;back to Write
dec i2cmmState ;1 ;back to StartWrite
retp ;3 = 10 + 7 = 17
:i2cmmWriteDone
inc i2cmmState ;1 ;move on to next state (stop)
retp ;3 = 10 + 7 = 17 ;and start the stop bit
;*********************************************************************************
; State: i2cmmStop
; This state puts a stop condition on the I2C bus and resets the state machine back
; to its idle state. A stop condition is when SDA goes from low to high while SCL
; is high.
;*********************************************************************************
i2cmmStop mov w,i2cmmSubState ;1
; The code between the tableStart and tableEnd statements
; MUST be completely within the first half of a page. The routines
tableStart ; it is jumping to must be in the same page as this table.
add pc,w ;3
jmp :state1 ;3
jmp :state2 ;3
jmp :state3 ;3 = 7 + 7 = 14
tableEnd
:state1 setb i2cmmInControl ;1
clrb i2cmmPortBuf.sda ;1
inc i2cmmSubState ;1
retp ;3 = 6 + 14 = 20
:state2 setb i2cmmPortBuf.scl ;1
inc i2cmmSubState ;1
retp ;3 = 5 + 14 = 19
:state3 setb i2cmmPortBuf.sda ;1
clr i2cmmSubState ;1
clr i2cmmState ;1 ;put the state machine in Idle
clr i2cmmNumBytes ;1
mov w,#$ff ;1
mov i2cmmIndex,w ;1
clrb i2cmmInControl ;1
retp ;3 = 10 + 14 = 24
;*****************************************************************************************
; End of I2C Master state machine
;*****************************************************************************************
;*****************************************************************************************
; Jump table
;*****************************************************************************************
i2cmmSendByte jmp i2cmmSendByte_ ;3
i2cmmSendBytes jmp i2cmmSendBytes_ ;3
i2cmmGetByte jmp i2cmmGetByte_ ;3
i2cmmGetBytes jmp i2cmmGetBytes_ ;3
i2cmmWaitNotBusy jmp i2cmmWaitNotBusy_ ;3
i2cmmInit jmp i2cmmInit_ ;3
;*****************************************************************************************
; I2C Master Subroutines
;*****************************************************************************************
;*********************************************************************************
; Function: i2cmmStartRead
; This state simply loads the contents of the i2cmmAddress register into the
; i2cmmByte register and sets up the i2cmmWrite state to output the address
; of the slave to read.
;*********************************************************************************
i2cmmStartRead
mov w,i2cmmAddress
mov i2cmmByte,w
inc i2cmmIndex
mov w,#8
mov i2cmmBitCount,w
inc i2cmmState
retp
;*********************************************************************************
; Function: i2cmmReadData
; This function prepares the I2CM read routine so it can read from the slave
; device. It initializes the bit count, etc.
;*********************************************************************************
i2cmmReadData
mov w,#8
mov i2cmmBitCount,w
inc i2cmmState
;*************************************************************************
; Read 8 bits of data from the slave device.
;*************************************************************************
i2cmmRead mov w,i2cmmSubState
; The code between the tableStart and tableEnd statements
; MUST be completely within the first half of a page. The routines
tableStart ; it is jumping to must be in the same page as this table.
add pc,w
jmp :state1
jmp :state2
jmp :state3
tableEnd
:state1 clrb i2cmmInControl
setb i2cmmPortBuf.scl
inc i2cmmSubState
retp
:state2 sb i2cmmSclPin
retp
stc
sb i2cmmSdaPin
clc
rl i2cmmByte
inc i2cmmSubState
retp
:state3 clrb i2cmmPortBuf.scl
clr i2cmmSubState
dec i2cmmBitCount
sb z
retp
inc i2cmmState
retp
;*********************************************************************************
; Function: i2cmmStoreByte
; This function stores the byte just read into the buffer.
;*********************************************************************************
i2cmmStoreByte
mov w,i2cmmByte
mov isrTemp0,w
inc i2cmmIndex
mov w,i2cmmIndex
add fsr,w
mov w,isrTemp0
mov indf,w
inc i2cmmState
setb i2cmmRxFlag
retp
;*********************************************************************************
; Function: i2cmmSendAck
; This function sends an ack if there is data left to write, and a NACK if
; there is no data left to write.
;*********************************************************************************
i2cmmSendAck
mov w,i2cmmSubState
; The code between the tableStart and tableEnd statements
; MUST be completely within the first half of a page. The routines
tableStart ; it is jumping to must be in the same page as this table.
add pc,w
jmp :state1
jmp :state2
jmp :state3
jmp :state4
tableEnd
:state1 setb i2cmmInControl
clrb i2cmmPortBuf.sda
mov w,i2cmmIndex
xor w,i2cmmNumBytes
snz
setb i2cmmPortBuf.sda
inc i2cmmSubState
retp
:state2 setb i2cmmPortBuf.scl ;Pulse the clock
inc i2cmmSubState
retp
:state3 sb i2cmmSclPin
retp
clrb i2cmmPortBuf.scl
inc i2cmmSubState
retp
:state4 setb i2cmmPortBuf.sda
clr i2cmmSubState
mov w,i2cmmIndex
xor w,i2cmmNumBytes
snz
jmp :done
mov w,#(i2cmmReadRptLoc - i2cmmIdleLoc) ;back to read
mov i2cmmState,w
retp
:done inc i2cmmState ;If this was the last byte to be read, send a stop
retp
;*****************************************************************************************
; I2C Master Subroutines: Mainline Access routines (call from the mainline)
;*****************************************************************************************
;*********************************************************************************
; Function: i2cmmSendByte
; This routine sets up the I2CM state machine to write the byte of data in
; the i2cmmDataBuf register. Before entering this routine, make sure that
; the I2CM state machine is in its idle state (use the i2cmmWaitNotBusy
; subroutine) and that the i2cmmAddress is loaded with the address of the
; slave that this byte is going to, and that i2cmmDataBuf is loaded with the
; data to send.
;*********************************************************************************
i2cmmSendByte_
mov w,#1 ;There is one byte of data in the buffer
mov i2cmmNumBytes,w
;*********************************************************************************
; Function: i2cmmSendBytes
; This routine sets up the I2CM state machine to write the bytes of data in
; the i2cmmDataBuf registers. Before entering this routine,
; make sure that the I2CM state machine is in its idle state (use the
; i2cmmWaitNotBusy subroutine) and that i2cmmAddress is loaded with the
; address of the slave that this byte is going to, that i2cmmDataBuf
; are loaded with the data to send, and that the i2cmmNumBytes register
; is loaded with the number of data bytes to send.
;*********************************************************************************
i2cmmSendBytes_
setb i2cmmDoingWrite
mov w,#%11111110
and i2cmmAddress,w
clrb i2cmmNack
mov w,#(i2cmmWriteLoc-i2cmmIdleLoc)
mov i2cmmState,w
retp
;*********************************************************************************
; Function: i2cmmWaitNotBusy
; This routine polls the i2cmmState register until it is not busy. It returns
; when the I2C master state machine becomes idle. It returns a (0) in the w
; register if the transfer appeared successful (ie. The slave returned an ACK
; when addressed), and a (1) in the w register if the slave did not return
; an ack when addressed/written.
;*********************************************************************************
i2cmmWaitNotBusy_
:wait_loop test i2cmmState
sb z ; wait until I2C is idle
jmp :wait_loop
mov w,#1 ; return (1) if we are idle because a NACK was
snb i2cmmNack ; received. Return (0) if we are idle because
retp ; this was successful
clr w
retp
;*********************************************************************************
; Function: i2cmmGetByte
; This routine gets one byte of data from the slave at address i2cmmAddress.
; before calling this routine, ensure that the I2C Master State Machine is
; in its idle state (use the i2cmmWaitNotBusy subroutine) and that the
; i2cmmAddress register is loaded with a valid address. The routine returns
; with the byte received in the w register and in the i2cmmDataBuf register.
;*********************************************************************************
i2cmmGetByte_
clrb i2cmmDoingWrite
:nack mov w,#%00000001
or i2cmmAddress,w
mov w,#1
mov i2cmmNumBytes,w
clrb i2cmmNack
mov w,#(i2cmmReadLoc-i2cmmIdleLoc)
mov i2cmmState,w
call i2cmmWaitNotBusy
and w,#$ff
sz
jmp :nack
clrb i2cmmRxFlag
mov w,i2cmmDataBuf
retp
;*********************************************************************************
; Remaining functions (i2cmmGetBytes and i2cmmInit) is moved to PAGE4_ORG
; because of insufficient space in this page...
;*********************************************************************************
;VP_end ; End cut/paste for I2C MultiMaster
;*****************************************************************************************
org STRINGS_ORG ; This label defines where strings are kept in program space.
;*****************************************************************************************
;------------------------------------------------------------------------------
; Put String Data Here
;------------------------------------------------------------------------------
; Example:
;_hello dw 13,10,'UART Demo',0
jmp $ ; This instruction will cause an assembler error if the source code before
; the org statement inadvertantly crosses a page boundary.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; - Routines that use location-dependant data, such as in example below, should
; use a LABEL rather than a literal value as their input. Example:
; instead of
; mov m,#3 ; move upper nybble of address of strings into m
; use
; mov m,#STRINGS_ORG>>8; move upper nybble of address of strings into m
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
;*****************************************************************************************
org PAGE3_ORG
;*****************************************************************************************
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; To ensure that several Virtual Peripherals, when pasted together, do not cross
; a page boundary without the integrator's knowledge, put an ORG statement and one
; instruction at every page boundary. This will generate an error if a pasted
; subroutine moves another subroutine to a page boundary.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
jmp $ ; This instruction will cause an assembler error if the source code before
; the org statement inadvertantly crosses a page boundary.
;*****************************************************************************************
org PAGE4_ORG
;*****************************************************************************************
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
; To ensure that several Virtual Peripherals, when pasted together, do not cross
; a page boundary without the integrator's knowledge, put an ORG statement and one
; instruction at every page boundary. This will generate an error if a pasted
; subroutine moves another subroutine to a page boundary.
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
;VP_begin I2C Multi-Master
;*********************************************************************************
; FUNCTIONS moved from SUBROUTINES because of insufficient space
;*********************************************************************************
;*********************************************************************************
; Function: i2cmmGetBytes
; This routine gets i2cmmNumBytes of data from the slave at address
; i2cmmAddress. Before calling this routine, ensure that the I2CM state
; machine is idle by using the i2cmmWaitNotBusy subroutine, that i2cmmAddress
; register contains the address of the slave to be read from, and that the
; i2cmmNumBytes register is loaded with the number of bytes of data to receive.
; The received bytes will be contained in registers i2cmmDataBuf.
;*********************************************************************************
i2cmmGetBytes_
clrb i2cmmDoingWrite
mov w,#%00000001
or i2cmmAddress,w
clrb i2cmmNack
clrb i2cmmRxFlag
mov w,#(i2cmmReadLoc-i2cmmIdleLoc)
mov i2cmmState,w
retp
;*********************************************************************************
; Function: i2cmmInit
; This subroutine should be called on startup. It initializes the registers
; which are critical to the operation of the I2CM state machine.
;*********************************************************************************
i2cmmInit_
mov w,#%10111111 ;Set RB in/out directions
mov i2cmmPortBuf,w
mov w,#$ff
mov i2cmmNumBytes,w
mov w,#$ff
mov i2cmmIndex,w
retp
;VP_end ; End cut/paste for I2C MultiMaster
;*****************************************************************************************
org MAIN_PROGRAM_ORG
;*****************************************************************************************
;------------------------------------------------------------------------------
; RESET VECTOR
;------------------------------------------------------------------------------
;------------------------------------------------------------------------------
; Program execution begins here on power-up or after a reset
;------------------------------------------------------------------------------
_resetEntry
;------------------------------------------------------------------------------
; Initialize all port configuration
;------------------------------------------------------------------------------
_mode ST_W ;point MODE to write ST register
mov w,#RB_ST ;Setup RB Schmitt Trigger, 0 = enabled, 1 = disabled
mov !rb,w
mov w,#RC_ST ;Setup RC Schmitt Trigger, 0 = enabled, 1 = disabled
mov !rc,w
IFDEF SX48_52
mov w,#RD_ST ;Setup RD Schmitt Trigger, 0 = enabled, 1 = disabled
mov !rd,w
mov w,#RE_ST ;Setup RE Schmitt Trigger, 0 = enabled, 1 = disabled
mov !re,w
ENDIF
_mode LVL_W ;point MODE to write LVL register
mov w,#RA_LVL ;Setup RA CMOS or TTL levels, 0 = TTL, 1 = CMOS
mov !ra,w
mov w,#RB_LVL ;Setup RB CMOS or TTL levels, 0 = TTL, 1 = CMOS
mov !rb,w
mov w,#RC_LVL ;Setup RC CMOS or TTL levels, 0 = TTL, 1 = CMOS
mov !rc,w
IFDEF SX48_52
mov w,#RD_LVL ;Setup RD CMOS or TTL levels, 0 = TTL, 1 = CMOS
mov !rd,w
mov w,#RE_LVL ;Setup RE CMOS or TTL levels, 0 = TTL, 1 = CMOS
mov !re,w
ENDIF
_mode PLP_W ;point MODE to write PLP register
mov w,#RA_PLP ;Setup RA Weak Pull-up, 0 = enabled, 1 = disabled
mov !ra,w
mov w,#RB_PLP ;Setup RB Weak Pull-up, 0 = enabled, 1 = disabled
mov !rb,w
mov w,#RC_PLP ;Setup RC Weak Pull-up, 0 = enabled, 1 = disabled
mov !rc,w
IFDEF SX48_52
mov w,#RD_PLP ;Setup RD Weak Pull-up, 0 = enabled, 1 = disabled
mov !rd,w
mov w,#RE_PLP ;Setup RE Weak Pull-up, 0 = enabled, 1 = disabled
mov !re,w
ENDIF
_mode DDIR_W ;point MODE to write DDIR register
mov w,#RA_DDIR ;Setup RA Direction register, 0 = output, 1 = input
mov !ra,w
mov w,#RB_DDIR ;Setup RB Direction register, 0 = output, 1 = input
mov !rb,w
mov w,#RC_DDIR ;Setup RC Direction register, 0 = output, 1 = input
mov !rc,w
IFDEF SX48_52
mov w,#RD_DDIR ;Setup RD Direction register, 0 = output, 1 = input
mov !rd,w
mov w,#RE_DDIR ;Setup RE Direction register, 0 = output, 1 = input
mov !re,w
ENDIF
mov w,#RA_latch ;Initialize RA data latch
mov ra,w
mov w,#RB_latch ;Initialize RB data latch
mov rb,w
mov w,#RC_latch ;Initialize RC data latch
mov rc,w
IFDEF SX48_52
mov w,#RD_latch ;Initialize RD data latch
mov rd,w
mov w,#RE_latch ;Initialize RE data latch
mov re,w
ENDIF
;------------------------------------------------------------------------------
; Clear all Data RAM locations
;------------------------------------------------------------------------------
zeroRam
IFDEF SX48_52 ;SX48/52 RAM clear routine
mov w,#$0a ;reset all ram starting at $0A
mov fsr,w
:zeroRam clr ind ;clear using indirect addressing
incsz fsr ;repeat until done
jmp :zeroRam
_bank bank0 ;clear bank 0 registers
clr $10
clr $11
clr $12
clr $13
clr $14
clr $15
clr $16
clr $17
clr $18
clr $19
clr $1a
clr $1b
clr $1c
clr $1d
clr $1e
clr $1f
ELSE ;SX18/20/28 RAM clear routine
clr fsr ;reset all ram banks
:zeroRam sb fsr.4 ;are we on low half of bank?
setb fsr.3 ;If so, don't touch regs 0-7
clr ind ;clear using indirect addressing
incsz fsr ;repeat until done
jmp :zeroRam
ENDIF
;------------------------------------------------------------------------------
; Initialize program/VP registers
;------------------------------------------------------------------------------
;VP_begin I2C Multi-Master
_bank i2cmmBank
call @i2cmmInit
;VP_end ; End cut/paste for I2C MultiMaster
;------------------------------------------------------------------------------
; Setup and enable RTCC interrupt, WREG register, RTCC/WDT prescaler
;------------------------------------------------------------------------------
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
; Virtual Peripheral Guidelines Tip:
;
; The suggested default values for the option register are:
; - Bit 7 set to 0: location $01 addresses the W register (WREG)
; - Bit 3 set to 1: Prescaler assigned to WatchDog Timer
;
; If a routine must change the value of the option register (for example, to access
; the RTCC register directly), then it should restore the default value for the
; option register before exiting.
;
;?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?
RTCC_ON = %10000000 ;Enables RTCC at address $01 (RTW hi)
;*WREG at address $01 (RTW lo) by default
RTCC_ID = %01000000 ;Disables RTCC edge interrupt (RTE_IE hi)
;*RTCC edge interrupt (RTE_IE lo) enabled by default
RTCC_INC_EXT = %00100000 ;Sets RTCC increment on RTCC pin transition (RTS hi)
;*RTCC increment on internal instruction (RTS lo) is default
RTCC_FE = %00010000 ;Sets RTCC to increment on falling edge (RTE_ES hi)
;*RTCC to increment on rising edge (RTE_ES lo) is default
RTCC_PS_ON = %00000000 ;Assigns prescaler to RTCC (PSA lo)
RTCC_PS_OFF = %00001000 ;Assigns prescaler to WDT (PSA hi)
PS_000 = %00000000 ;RTCC = 1:2, WDT = 1:1
PS_001 = %00000001 ;RTCC = 1:4, WDT = 1:2
PS_010 = %00000010 ;RTCC = 1:8, WDT = 1:4
PS_011 = %00000011 ;RTCC = 1:16, WDT = 1:8
PS_100 = %00000100 ;RTCC = 1:32, WDT = 1:16
PS_101 = %00000101 ;RTCC = 1:64, WDT = 1:32
PS_110 = %00000110 ;RTCC = 1:128, WDT = 1:64
PS_111 = %00000111 ;RTCC = 1:256, WDT = 1:128
OPTIONSETUP equ RTCC_ON | RTCC_PS_OFF ; the default option setup for this program.
mov w,#OPTIONSETUP ; setup option register for RTCC interrupts enabled
mov !option,w ; and prescaler assigned to WDT.
jmp @mainLoop
;------------------------------------------------------------------------------
; MAIN PROGRAM CODE
;------------------------------------------------------------------------------
mainLoop
;VP_begin I2C Multi-Master
;*****************************************************************************************
; MAIN PROGRAM CODE
; This can be changed as you like to suit your own application
; At present data is read from an EEPROM device and the data stored into the last RAM bank
;*****************************************************************************************
;*********************************************************************************
; Initialize variables...
;*********************************************************************************
_bank i2cmmBank
mov w,#i2cmmSlaveAddr ; set address of slave to read.
mov i2cmmAddress,w
_bank VARS ; clear read and write address pointers
clr i2cmmReadAdr
clr i2cmmWritePtr
;*********************************************************************************
; Read a character from EEPROM 'i2cmmAddress', at location 'i2cmmReadAdr'
;*********************************************************************************
i2cRead _bank VARS
mov w,i2cmmReadAdr
_bank i2cmmBank
mov i2cmmDataBuf,w ; load send register with data address
call @i2cmmWaitNotBusy ; wait for I2CM state machine to enter idle state
call @i2cmmSendByte ; send 'want to read' and bank addess to i2c slave
call @i2cmmWaitNotBusy ; wait for I2CM state machine to enter idle state
snb i2cmmLostArb ; if arbitration was lost then wait a while and try again
jmp iveLostArb
snb i2cmmNack ; Check for no acknowledge
jmp i2cmmGotNack ; Set lights for no Ack and try again
call @i2cmmGetByte ; Gets the byte from slave and returns it in w
snb i2cmmLostArb ; if arbitration was lost wait a while and then try again
jmp iveLostArb
snb i2cmmNack ; Check for no acknowledge
jmp i2cmmGotNack ; Set lights for no ack and try again
or w,#$00 ; check for null character, indicating end of string
snb z ; null char, end of string...restart
jmp mainLoop
mov i2cRecvChar,w ; save received character
; cjne i2cRecvChar,#'A',i2cmmBadData ; Check data received matches data saved in EEPROM
; for example store all 'A's in the EEPROM and confirm
; read data is an 'A'.
;*********************************************************************************
; Store the characters received in bank 7...
;*********************************************************************************
i2cmmStoreChar clrb i2cmmRedLed1
setb i2cmmGreenLed ; indicate data received okay
_bank VARS
mov w,#i2cmmRecvString
add w,i2cmmWritePtr
mov fsr,w
mov w,i2cRecvChar ; save revcd data to address pointed to by fsr
mov indf,w
_bank VARS
inc i2cmmReadAdr ; set to read next address
inc i2cmmWritePtr ; increment offset of where to save data
snz
jmp mainLoop ; finished reading entire EEPROM bank... Restart
jmp i2cRead ; read another character from eeprom
;*********************************************************************************
; This Master will wait here when arbitration is lost
;*********************************************************************************
iveLostArb clrb i2cmmGreenLed
snb i2cmmRedLed2 ; This master has lost arbitration
jmp i2cmmLedOn
i2cmmLedOff setb i2cmmRedLed2 ; Toggle green LED
jmp i2cmmWaitHere
i2cmmLedOn clrb i2cmmRedLed2
i2cmmWaitHere _bank i2cmmTimer ; Wait a 'random' time before trying again
test i2cmmTimerLow
sz
jmp i2cmmWaitHere
_bank i2cmmBank
clrb i2cmmLostArb
jmp mainLoop ; Retry I2C operation
;*********************************************************************************
; ERROR CONDITIONS:
;*********************************************************************************
i2cmmGotNack setb i2cmmGreenLed
setb i2cmmRedLed1
setb i2cmmRedLed2
jmp mainLoop ; Did not get an acknowledge from slave
i2cmmBadData setb i2cmmRedLed1
clrb i2cmmRedLed2
clrb i2cmmGreenLed
mov w,i2cRecvChar ; Got incorrect data from EEPROM
jmp $ ; should never occur
;VP_end ; End cut/paste for I2C MultiMaster
jmp mainLoop
;*****************************************************************************************
END ;End of program code
;*****************************************************************************************
;*****************************************************************************************
;*****************************************************************************************
;*****************************************************************************************
;*****************************************************************************************
;*****************************************************************************************
;*****************************************************************************************
| file: /Techref/scenix/lib/io/osi2/i2c/i2c_dual_multi_master.src, 84KB, , updated: 2001/10/18 10:39, local time: 2024/11/12 11:35,
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Ashley Roll has put together a really nice little unit here. Leave off the MAX232 and keep these handy for the few times you need true RS232! |
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