Post by thread:[PIC]: I hoped it didn't come to this

Well I have been trying to get a 16f84A to read data from a TLC548 and have absolutely no experience and knowledge how to do it. I have 84a 548 RB.0 connected to Data out (6) RB.1 I/O clock (7) RB.2 CS (5) with the following code. (I don't mind being emarressed) temp VAR WORD cnt VAR WORD cnt = 0 start: cnt = cnt + 1 GoSub Serialin SerOut PORTB.7,4,["here = ",#cnt,"temp = ",#temp,10,13] ' sends info to term Pause 1000 GoTo start Serialin: Pause 500 Low PORTB.2 ShiftIn PORTB.0,PORTB.1,4,[temp] Pause 500 High PORTB.2 Return HELP PLEASE? -- 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

You defined temp as a WORD (16 bits), but your SHIFTIN statement only sends out 8 bits (the default)! Change it to: ShiftIn PORTB.0,PORTB.1,4,[temp\16] {Original Message removed}

Thanks Terry. Can you see any other probs? I am amazed I am even that close. I was also wondering if I had guessed the correct mode (4) for that particular chip as in MSB FIRST | Read data before clock (clock idles low) This is all guess work so far. I have a long way to go and am doing bits and pieces at a time {Original Message removed}

I myself am new to PICBASIC programming, so I may not be much help! The only other problem that I can see is that you PAUSE 500 before returning PORTB.2 high after SHIFTIN. There is no need for this. In fact,it introduces the opportunity for 'noise' spikes to enter the device and be seen as clocks. Also remember that the MSB is available AS SOON AS PORTB.2 goes low, prior to any clocks! Regards Terry {Original Message removed}

I have always assumed that you have previously set your TRIS register as follows: TRISB = %00000001 This sets PORTB.0 as an INPUT, and the remainder as OUTPUTS! Regards Terry {Original Message removed}