Post by thread:Re: [PIC]: LCD From 16F84 to 16F877

> > i'm working with a LCD (HD44780, 2x16 4 wire mode) i used code from >called WKTIM4M.ASM (thx :). This worked great with a 16F84 but now i want >to use it at an 16F877 but it won't work. > > bsf STATUS, RP0 > > movlw B'00000000' ; RE all as outputs > > movwf TRISE > > movlw B'00001111' ; RD7-RD4 outputs others Input > > movwf TRISD > > bcf STATUS, RP0 This probably doesn't affect anything you're doing here, but it's worth mentioning that in changing from a 16F84 to a 16F87x chip, you have to concern yourself with the RP1 status bit as well as the RP0 bit when selecting banks. To be correct, use bcf STATUS, RP1 and bsf STATUS, RP0 for bank 1. It could trick you up, especially since some files can be accessed through banks 0 and 2, and 1 and 3. Unless you know from where you're coming in your code, you should try to set both bank bits to what you really need, not just the RP0 bit. --Andrew _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Aart, You were using a 4Mhz Xtal on the '84, and you also using a 4Mhz Xtal on the'877, if not you might want to check the delay routines for the LCD init are correct. Here is a snippit of code I use to give 100us delay LCD_D1 equ 0x30 LCD_D2 equ 0x31 #DEFINE LCD_xtal 0xA5 ;This should divide the clock to be 100us LCD_delay MOVWF LCD_D1 LCD_delay1 MOVLW LCD_xtal MOVWF LCD_D2 LCD_delay2 DECFSZ LCD_D2,F GOTO LCD_delay2 DECFSZ LCD_D1,F GOTO LCD_delay1 RETURN My init code is like this :- LCD_init LCD_delaym 150 ;Delay 15ms LCD_nibble LCD_4_init ;First Init Byte LCD_delaym 41 ;Delay 4.1ms LCD_nibble LCD_4_init ;Second Init Byte LCD_delaym 1 ;Delay 100us LCD_nibble LCD_4_init ;Third Init Byte LCD_delaym 41 ;Delay 4.1ms LCD_nibble LCD_4_mode_n ;Set 4 bit interface, busy flag now readable, from this point on use busy flag on not time delays LCD_command LCD_4_2_5x8 ;Select 2 line 5X8 4 bit mode LCD_command LCD_disp ;Display off Command LCD_command LCD_disp | LCD_d_on ;Display on, Cursor off LCD_command LCD_i_right ;Increment Cursor, No Scroll LCD_command LCD_clear ;Clear the display RETURN I include the LCD_init not for use as you have on that works anyway, but just to show the timings I use with LCD_delaym which is just a macro to move the litral to W and call LCD_delay. LCD_delaym macro argv MOVLW argv CALL LCD_delay endm I can let you have the full source if you want it, just ask. Regards Ben Please respond to pic microcontroller discussion list <spam_OUTPICLISTTakeThisOuTMITVMA.MIT.EDU> To: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU cc: (bcc: Ben SUFFOLK/EN/HTLUK) Subject: Re: [PIC]: LCD From 16F84 to 16F877 {Quote hidden}> PORTE will be in ANALOG mode. > > Change the ADCON1 register to make it work in digital mode. > > bsf STATUS,RP0 > movlw 6h ; all analog pins = digital > movwf ADCCON1 > bcf STATUS,RP0 > > > Make sure the unused pins on the other ports are set as outputs. >Tony Hi, The code is now changed (as above) all unused pins were set as output and i made sure i was refering to the right page: bcf STATUS, RP1 bsf STATUS, RP0 ---code--- There was a slight change, there are some characters (all the same and unreadable) at the display now when turning on. Maybe somone would take a look at the full code (it's short). http://aart.myip.org/test/ the 84 code is working and the 877 aint, i'm using a bootloader these are the first few lines. Thanks a lot, Aart. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. - att1.eml ******************************************************************************* Important. This E-mail is intended for the above named person and may be confidential and/or legally privileged. If this has come to you in error you must take no action based on it, nor must you copy or show it to anyone; please inform the sender immediately. ******************************************************************************* -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservKILLspammitvma.mit.edu with SET PICList DIGEST in the body

> Not necessary anymore.. IT WORKS! i made a mistake with the CBLOCK, didn't > change the variable "CBLOCK 0Ch" to "CBLOCK 20h" which is necessary > for the '877. Yet another reason for using relocatable mode and the RES directive. Too bad you can't go back and spend the time wasted on this bug to learn about relocatable mode instead. ******************************************************************** Olin Lathrop, embedded systems consultant in Littleton Massachusetts (978) 742-9014, EraseMEolinspam_OUTTakeThisOuTembedinc.com, http://www.embedinc.com -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listservspam_OUTmitvma.mit.edu with SET PICList DIGEST in the body