Post by thread:[PIC]: output from ADRES register using PIC12C672

I've had no experience with PIC's before, but I am trying to use a PIC12C672 to do A/D conversions. My problem is that I'm unsure of how to set up the I/O pins so that I can tranfer the results from the ADRES register to them. I am only using 1 pin for an analog input (CH0) and I think my code is correct so far. I just need some kind of a detailed example of how I should output my results. I've looked in the data sheets, but that really doesn't help a first time user, who has never programmed in assembly before. Thanks, Matt Willman ____________________________________________________________________ Get your own FREE, personal Netscape WebMail account today at http://webmail.netscape.com. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]: PIC only [EE]: engineering [OT]: off topic [AD]: advertisements

Matt, Not trying to be sarchastic, but why do you want to take in an analog voltage, convert it to a digital word (byte), and then send it right back out of the processor? If that's what you need, just get a standalone A/D, and go from there. From my point of view, the whole point of having an A/D on board is to be able to sample an analog signal, convert it to digital, then use that result inside the uC to be able to make decisions on what to do next, such as turn on or off an output to control a lamp for instance. And if you're bent on getting the digital word out of the processor, you'll either have to take it 4 bits at a time or do it serially. The reason being you only have 6 'Input' pins and 5 'Output' pins, so naturally, you can't send 8 bits out of a 5 bit port. Regards, Jim On Thu, 13 July 2000, Matt Willman wrote: {Quote hidden}> > I've had no experience with PIC's before, but I am trying to use a PIC12C672 > to do A/D conversions. My problem is that I'm unsure of how to set up the I/O > pins so that I can tranfer the results from the ADRES register to them. I am > only using 1 pin for an analog input (CH0) and I think my code is correct so > far. I just need some kind of a detailed example of how I should output my > results. I've looked in the data sheets, but that really doesn't help a first > time user, who has never programmed in assembly before. > > Thanks, > Matt Willman > > ____________________________________________________________________ > Get your own FREE, personal Netscape WebMail account today at http://webmail.netscape.com. > > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]: PIC only [EE]: engineering [OT]: off topic [AD]: advertisements spam_OUTjimTakeThisOuTjpes.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]: PIC only [EE]: engineering [OT]: off topic [AD]: advertisements

Somehow getting the analog value into digital form for me to look at would definitely be something I'd do during testing. This chip is an eight pin device, isn't it? You could put a few of the bits of the value onto some of the output pins. You could clock it out as serial. -- James Cameron .....quozlKILLspam@spam@us.netrek.org http://quozl.netrek.org/ -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]: PIC only [EE]: engineering [OT]: off topic [AD]: advertisements

Matt Willman wrote: > > I've had no experience with PIC's before, but I am trying to use a PIC12C672 > to do A/D conversions. My problem is that I'm unsure of how to set up the I/O > pins so that I can tranfer the results from the ADRES register to them. I am > only using 1 pin for an analog input (CH0) and I think my code is correct so > far. I just need some kind of a detailed example of how I should output my > results. I've looked in the data sheets, but that really doesn't help a first > time user, who has never programmed in assembly before. > > Thanks, > Matt Willman These simple serial routines may help. 19200 baud Fosc = 4MHz Receive can be polled or interrupt driven. ; ; ---------------- ; TRANSMIT ROUTINE ; ---------------- ; TxRoutine movwf TxSend ; temp store data to be sent bcf PORT,TX ; do start bit call HBDelay5 call HBDelay2 ; movlw 8h ; 8 data bits to send movwf BCount ; TxLoop rrf TxSend btfsc STATUS,C goto TxHiBit ; nop bcf PORT,TX goto DoneBit ; TxHiBit bsf PORT,TX goto $ + 1 ; DoneBit call HBDelay5 ; wait 1 bit length call HBDelay5 decfsz BCount goto TxLoop ; call DoRet nop bsf PORT,TX ; stop bit call HBDelay1 call HBDelay DoRet return ; ; ; --------------- ; RECEIVE ROUTINE ; --------------- ; RxRoutine bcf flag1,data btfsc PORT,RX ; wait for start bit return ; call HBDelay2 ; wait 1/2 bit length - 2 cycles movlw 9h movwf BCount ; RxLoop btfsc PORT,RX ; start bit is lost during routine goto RxHiBit ; bcf STATUS,C ; receive start bit and 8 data bits goto RxLoBit ; RxHiBit bsf STATUS,C nop RxLoBit rrf RxHold call HBDelay4 ; wait 1/2 bit length - 4 cycles call HBDelay5 ; wait 1/2 bit length - 5 cycles decfsz BCount goto RxLoop ; movf RxHold,W bsf flag1,data return ; data returned in W Reg ; ; -------------- ; HALF BIT DELAY ; -------------- ; HBDelay nop HBDelay1 nop HBDelay2 goto $ + 1 HBDelay4 nop HBDelay5 movlw 0x05 movwf BitWait BW decfsz BitWait goto BW nop return -- Best regards Tony mICro's http://www.picnpoke.com salesKILLspampicnpoke.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Before the days of ICD, I used this routine to show a register on my 'scope. Connect the synch to channelA use this channel as trigger. The short "1" in the output string is markers between bits. This was with 4MHz. If you want slower on scope, use delay routines instead of NOPs. Quentin ;USE PORTA, 2 AND 3 ;CODE EXAMPLE BSF PORTA,2 ;SYNCH PULSE NOP NOP NOP BCF PORTA,2 MOVF SMHI,W ;register to test MOVWF TEMP CALL TEREG ;SUBS TEREG BSF PORTA,3 ;STRING:101XXX1XXX1XXX1XXX1XXX1XXX1XXX1XXX NOP BCF PORTA,3 MOVLW 0X08 MOVWF TEMP1 TST NOP BSF PORTA,3 NOP BCF PORTA,3 BTFSS TEMP,7 GOTO BITOUT BSF PORTA,3 BITOUT BCF STATUS,C RLF TEMP,F NOP NOP NOP NOP NOP NOP BCF PORTA,3 DECFSZ TEMP1,F GOTO TST RETLW 0 -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics