Ok, I have tried EVERYTHING possible in trying to get this I2C working, but I
can't :-( I have gone back to trying to get a successful ACK now, and can't do
it. Here is the code I'm using below, just to write one byte of data (the
address 1001 0000)... using an 16f877 with Port C pins 3 and 4. And I have
checked all my #define's to make sure they refer to the right thing. Help
PLEASE!!!

TGetTemp

 bank1

 movlw b'00011000'
 iorwf TRISC,f

 movlw 0x09                 ;This will hold our Baud Rate!
 movwf SSPADD
 bcf SSPSTAT,6              ; select I2C input levels
 bcf SSPSTAT,7              ;
 bank0
 movlw b'00101000'
 movwf SSPCON

 bank1
 bsf _SEN                   ;Enable the start bit tx.
 btfsc _SEN                 ;Check to see when it's done.
  goto $-1
 bank0

 movlw b'10010000'          ;Move the address and tx it.
 movwf SSPBUF
 bank1
 btfsc SSPSTAT,R_W          ;Check to see when it's done.
  goto $-1
 movlw 0x00
 btfss _ACKSTAT          ;successful if the ACKSTAT bit is clear. 1 = success.
  movlw 0x01

 bank0

 call LCDBin               ;Print either 0 or 1.

return


Quoting Martin.Buehler@KEYMILE.COM:

> that's not too odd.
> i only use software i2c as this allows me to run i2c at 1kHz, allowing
> long distance i2c.
> it also allows me to use the same periphery drivers on all pics.
> tino
>
>
>
>
>
> "Alan B. Pearce" <A.B.Pearce@RL.AC.UK>
> Gesendet von: pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>
> 03.02.03 16:33
> Bitte antworten an pic microcontroller discussion list
>
>
>         An:     PICLIST@MITVMA.MIT.EDU
>         Kopie:
>         Thema:  Re: [PIC]: f877 I2C routines
>
>
> >And I shouldn't be communicating using bsf/bcf on
> >the ports.. instead use the TRIS bits? This seems odd.
>
> What is even more odd is why you seem to be using a software bit bang of
> the
> I2C instead of using the internal MSSP I2C hardware. Your subject line
> says
> you are using an 877 which has this and it is real easy to use.
>
> And yes, you should be using pull up resistors on both the clock and data
> line as your PIC should have both lines as "open collector" types. This is
> done automatically by the MSSP hardware, but is why you need to use the
> TRIS
> registers to set the bits to a 0 state when doing a bit bang
> implementation.
>
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