Post by thread:IR coding - decoding with PIC

Hallo all, Of course this has been asked before. I cannot find the codes that are transmitted by my TV/VCR remote control. I see signals on the scope and want to do something with it but... So: where can I find the standard codes? (read something about ISI ASCII) but ISI site is too full of info and no search engine Is the decoding software in the public domain (for 16F84 for instance)? Henk - VK2GWK

Hello the codes you look for are pwm so you have to do bit test feed the get an IR sensor put one leg to earth and the other to 5v through a 10k resistor the high leg then feed to pic on input pin then test this pin for high or low ect if you play around with the timeing ect adding nops to bit test you will get a value for a long pulse and a short pulse add the long and short pulses up to get value this value will be different when you press a different remote key. if you want some sample code i have it for 12c508

<x-flowed>Can you send me the IR codes to?? Manny Thanks, Joep Schroen ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com </x-flowed>

The codes are (IIRC) always PWM for the TV remotes. Unfortunately, each manufacturer has a bit different codes for their particular machine. While there are tons of sites about all this, the best tutor for actually programming for it was given to me by Don Roy (his webiste is http://www3.sympatico.ca/donroy) . His code for it is in his newsletter archive, but I also have an unmodified version of it at : http://204.233.101.40/robots/irremote.txt It is Stamp 2 code, so it is easy to figure out what is happening. The particular example decodes a Sony remote controller output and sends it back to the PC in ASCII number format. Easy to modify - used it to control robots with the TV remote - works great. Dan {Original Message removed}

there is not a set code this you will have to find your self with pic and ir sensor once you have a hex value for a key press then you can reverse the pic code to send back out to ir transmitter what is it that you want to do ??? what remote is it for ? what code have you written so far?

At 05:28 PM 10/24/99 +1000, you wrote: >Hallo all, >Of course this has been asked before. I cannot find the codes that are >transmitted by my TV/VCR remote control. I see signals on the scope and want >to do something with it but... >So: >where can I find the standard codes? (read something about ISI ASCII) but >ISI site is too full of info and no search engine >Is the decoding software in the public domain (for 16F84 for instance)? >Henk - VK2GWK It is now if it wasn't before. My code (a beginner's hack from start to finish for the JVC RM-RXC30) is below. I used this on a 16F84 with four common anode 7-segment displays on portb and digit driver PNP transistors on porta.0-3. The input from the ir demodulator is on porta.4. Drive with a 4MHz crystal. With my remote, the code is always F9xx, so I test for the F9 before setting the digits. Yours may be differerent, so try disabling that check. As to standard codes, I don't think there are any in practice - I looked at 6 remotes on my scope - not one looked anything like the other. They all had different transmission rates and pulse widths, some PWM, some fixed pulse width. Enjoy. ;Firewall Fred's public domain code for the JVC RM-RXC30 IR remote. Use and abuse freely. processor 16f84 include <p16f84.inc> __config _XT_OSC & _WDT_OFF & _PWRTE_ON J equ H'1F' ; J = address hex 1F K equ H'1E' ; K = address hex 1E L equ H'1C' ; L.0-L.3=digit0 L.4-L.7=digit1 M equ H'1B' ; M.0-M.3=digit2 M.4-M.7=digit3 DigEn equ H'1A' ;turn on bits 0-3 to enable digit 0-3 w_temp equ H'19' ; rxlow equ H'17' ;ir code, lsb rxhigh equ H'16' ;ir code, msb rxbits equ H'15' ;ir code length rxlow1 equ H'14' ;ir code, lsb for confirmation rxhigh1 equ H'13' ;ir code, msb for confirmation goodthresh equ H'12' ;ir code, msb for confirmation ;======================================= ; Initialization ;======================================= org 0 ; start at address 0 goto config nop nop nop goto INTERRUPT config: movlw B'00010000' ; Set port a.4=in A.3-A.0=out tris PORTA movlw B'00000000' ; Set port B.7-B.0 as output tris PORTB movlw B'00000001' movwf DigEn ;begin refresh on digit0 movlw H'00' movwf L movwf M movlw H'03' movwf goodthresh movlw H'03' option ;prescale to 1:16 movlw H'A0' ;GIE & T0IE set, T0IF cleared movwf INTCON ;t0 interrupts now enabled main_loop: call high_3mS ;wait for 3mS of high (startbit) wtfrlow: btfsc PORTA,4 ;wait for logical low (first bit) goto wtfrlow movlw D'16' ;16 bits of data movwf rxbits clrf rxlow ;reset received code clrf rxhigh ;reset received code waitforhigh: ;get next bit btfss PORTA,4 goto waitforhigh call wait_100uS ;state determined after 700uS call wait_100uS call wait_100uS call wait_100uS call wait_100uS call wait_100uS call wait_100uS btfss PORTA,4 goto rxlowbit rxhighbit: bsf STATUS,C ;bit goes into carry for rotate goto recordbit rxlowbit: bcf STATUS,C ;bit goes into carry for rotate goto recordbit recordbit: rlf rxlow,f ;shift bit in rxlow.0, rxlow.7 >> C rlf rxhigh,f ;shift C >> rxhigh.0 waitforlow: btfsc PORTA,4 goto waitforlow checkiffinished: decfsz rxbits,f goto waitforhigh movfw rxlow subwf rxlow1,0 bz checkhighbyte ;good so far, check high byte goto bad_comp ;bad compare, get another one checkhighbyte: movfw rxhigh subwf rxhigh1,0 bz checkf9 ;good so far, check rxhigh for f9 goto bad_comp ;bad compare, get another one checkf9: movfw rxhigh sublw H'F9' bz good_comp ;good compare test for threshold goto bad_comp ;bad compare, get another one good_comp: decfsz goodthresh,f ;must be good n times goto main_loop movfw rxlow movwf L movfw rxhigh movwf M goto main_loop bad_comp: movlw D'3' ;reset test threshold movwf goodthresh movfw rxlow movwf rxlow1 movfw rxhigh movwf rxhigh1 goto main_loop ;======================================= ;high3mS: looks for 3mS of high on PORTA,4 ; instr = 3n + 5n^2 ;======================================= high_3mS: ;3000 instr at 4MHz movlw D'24' ;=2952 instr movwf J j3mS: movwf K ;K=J btfss PORTA,4 goto high_3mS ;start over if it goes low during wait k3mS: decfsz K,f ;K=K-1 goto k3mS ;5 instr per k loop decfsz J,f ;J=J-1 goto j3mS ;3 instr per j loop return ;======================================= ;Wait_100uS: Delays return for 100uS ;======================================= wait_100uS: ;100 instructions at 4MHz movlw D'31' movwf J ; J = 10 jloop: decfsz J,f ; J = J-1, skip next if zero goto jloop return INTERRUPT: movwf w_temp ;save W test1: btfsc DigEn,0 ;if on dig0, set dig0 goto setdig0 btfsc DigEn,1 ;if on dig1, set dig1 goto setdig1 btfsc DigEn,3 ;if on dig2, set dig2 goto setdig3 goto setdig2 ;if on dig3, set dig3 setdig0: movf PORTA,W ;clear dig enable ; andlw H'F0' ;(com cathode) iorlw H'0F' ;(com anode) movwf PORTA ; movf L,W ; andlw H'0F' ;keep lower nibble call seg_pat ;get seg pattern in w xorlw H'FF' ;(com anode) movwf PORTB ;and put in on the port ; bsf PORTA,0 ;then enable dig0 (com cathode) bcf PORTA,0 ;then enable dig0 (com anode) rlf DigEn,f ;adjust digit pointer goto restore_fi setdig1: movf PORTA,W ;clear dig enable ; andlw H'F0' ;(com cathode) iorlw H'0F' ;(com anode) movwf PORTA ; swapf L,0 ;reverse nibbles in L, result in W andlw H'0F' ;keep lower nibble call seg_pat ;get seg pattern in w xorlw H'FF' ;(com anode) movwf PORTB ;and put in on the port ; bsf PORTA,1 ;then enable dig1 (com cathode) bcf PORTA,1 ;then enable dig0 (com anode) rlf DigEn,f ;adjust digit pointer goto restore_fi setdig2: movf PORTA,W ;clear dig enable ; andlw H'F0' ;(com cathode) iorlw H'0F' ;(com anode) movwf PORTA ; movf M,W ; andlw H'0F' ;keep lower nibble call seg_pat ;get seg pattern in w xorlw H'FF' ;(com anode) movwf PORTB ;and put in on the port ; bsf PORTA,2 ;then enable dig1 (com cathode) bcf PORTA,2 ;then enable dig0 (com anode) rlf DigEn,f ;adjust digit pointer goto restore_fi setdig3: movf PORTA,W ;clear dig enable ; andlw H'F0' ;(com cathode) iorlw H'0F' ;(com anode) movwf PORTA ; swapf M,0 ;reverse nibbles in M, result in W andlw H'0F' ;keep lower nibble call seg_pat ;get seg pattern in w xorlw H'FF' ;(com anode) movwf PORTB ;and put in on the port ; bsf PORTA,3 ;then enable dig1 (com cathode) bcf PORTA,3 ;then enable dig0 (com anode) bcf DigEn,3 ;adjust digit pointer bsf DigEn,0 goto restore_fi restore_fi: movf w_temp,W ;restore W bcf INTCON,T0IF retfie seg_pat: addwf PCL,f ;bit.0=seg.a retlw B'00111111' ;0 retlw B'00000110' ;1 retlw B'01011011' ;2 retlw B'01001111' ;3 retlw B'01100110' ;4 retlw B'01101101' ;5 retlw B'01111101' ;6 retlw B'00000111' ;7 retlw B'01111111' ;8 retlw B'01100111' ;9 retlw B'01110111' ;a retlw B'01111100' ;b retlw B'00111001' ;c retlw B'01011110' ;d retlw B'01111001' ;e retlw B'01110001' ;f end Get HushMail. 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IR remote are not always PWM. The most widely used code, the RC5, is not PWM, but differential signal level, what confuse people to think it is pwm. If a person who never had deal with data communication look at the output wave form of a RC5 at scope, he will say it is pwm, but its not. Each bit transmitted in RC5 has the same length, and exactly in the middle of the bit it changes level. The level transition happens from one to zero if the bit is zero, from zero to one if the bit is one, so, the second half of the bit tells you what level the bit is. Transmitting mixed bit levels will generate patterns that someone can thinks is pwm. Example, sending bits combination of 01010101 will generate a square wave with half the frequency than sending only ones or zeros... but this is just because bits zeros start with high level, and ones with low level. bit 0: -_ bit 1: _- 0000 : -_-_-_-_ 1111 : _-_-_-_- 0101 : -__--__- 0011 : -_-__-_- Some other remotes use real PWM, with a double bit time for different level, they are not difficult, but demand some more work. RC5 is easy to decode, it is just as a serial data transmitted, you just need to produce a software serial reception routine, that samples the incoming data at the middle of the second half of each bit, it is the bit level. The bit train represent identifiers. For example, some bits identify the equipment, as TV, Radio, Tape, CD, DVD, Laser Disk, and more. Other bits means the key pressed or function. If you want to use a remote to control something else, go for Philips remotes, they use only 14 bits and low frequency modulation, even to sync at the scope :) so a 6 MHz uC can understand it perfectly. I already produced a device IR controlled, and used the Philips way, after testing Panasonic, Pioneer, JVC, and another bunch of codes produced by those 4in1 programmable remotes. Of course, as I produced the transmitter and receiver, I changed the codes, so not even the Philips remotes can interfere with my machine. I could use *any* bits combination or timings, but upon a jumper on the board allows me to return the receiver to understand Philips remotes. I am producing a web page about it, it is not finished, but I hope that what is ready helps you in anyway. Take a look at: http://www.ustr.net/infrared.shtml Wagner.

In message <002501bf1df1$564a58a0$865d868b@oemcomputer>, Agnes en Henk Tobbe <spam_OUTtobbeTakeThisOuTBIGPOND.COM> writes >Hallo all, >Of course this has been asked before. I cannot find the codes that are >transmitted by my TV/VCR remote control. I see signals on the scope and want >to do something with it but... It depend on the particular type of remote control, different makes use totally different coding and modulation schemes. The most common is the Philips RC5 system, this is used by many manufacturers, there has been source posted here for RC5 in the past. -- Nigel. /--------------------------------------------------------------\ | Nigel Goodwin | Internet : .....nigelgKILLspam@spam@lpilsley.demon.co.uk | | Lower Pilsley | Web Page : http://www.lpilsley.demon.co.uk | | Chesterfield | Official site for Shin Ki and New Spirit | | England | Ju Jitsu | \--------------------------------------------------------------/

<BLOCKQUOTE Author="Wagner Lipnharski"> IR remote are not always PWM. The most widely used code, the RC5, is not PWM, but differential signal level, what confuse people to think it is... http://www.ustr.net/infrared/infrared1.htm </BLOCKQUOTE> Great info! Thanks. James Newton jamesnewtonKILLspamgeocities.com phone:1-619-652-0593 http://techref.homepage.com NOW OPEN (R/O) TO NON-MEMBERS! Members can add private/public comments/pages ($0 TANSTAAFL web hosting) PICLIST guide: http://204.210.50.240/techref/default.asp?url=piclist.htm