I2CWrite Problem

[richard]

Unfortunately, it never checks the return value so it continues on with the rest of the bytes in the I2CWRITE statement (here you have four of them).

Not what i find . it may vary by pic18/16 and/or pbp version
i my test the transaction terminates at the first nak and is followed by a "funny start" dud transaction , the data in the sq brackets is never sent





pic18f45k80

'OSCTUNE.6 = 1 ; Enable 4x PLL
OSCCON = 110000




TRISD=000110 'set PORTD 


define OSC 16
DEFINE I2C_SLOW 1
ADR VAR BYTE
ADR2 VAR BYTE
CMD  VAR BYTE
ADR=$48
ADR2=$70   


SDA VAR PORTD.3
SCL VAR PORTD.2




CMD= $48


FEDO:
I2CWRITE SDA,SCL,ADR,[5]
I2CWRITE SDA,SCL,ADR2,CMD,[3,4]
PAUSE 250
I2CWRITE SDA,SCL,ADR,[0]
I2CWRITE SDA,SCL,ADR2,$48,[2,7]
PAUSE 250
GOTO FEDO

edit
might be a proteus artifact also, i have not scoped it

[tumbleweed]

That produces a slightly different result, but it's still wrong... there are extra transactions after getting a NACK to the first byte (slave address).
"S 02 N P" shouldn't be there, and I have a hunch that if you change "ADR2=$70" to something else you'll find that is wrong too.
I didn't bother trying to figure out exactly what it's sending, but it's not really what's in the remaining I2CWRITE statement.

I looked at the asm code in both cases and there's nothing I see to look at the ack/nack result of sending a byte, except to send a STOP and reset the internal state so the next byte starts a new transaction. There's nothing to "skip over sending the remaining bytes" in the I2CWRITE.