Another I2CWRITE problem

[ErnieM]

Ah ha! The 'data' portion of the transfer needs brackets. Otherwise the compiler accepts them as good but doesn't issue the I2C stop condition.

Another "feature" of PBP, a silent compile error.


Bob:

On the 16F88, PortB.1 and PortB.4 are used for I2C . (Datasheet!) B1 is the data line and B.4 is the clock line.

That would be true if PBP used the internal hardware for I2C. It doesn't, it just bit bangs the ports (well, actually the tris registers so it can do open collector type outputs). If you skim down a disasembly listing or memory listing (something MPLAB will get for you if you load both the hex and cod files) you'll see it doing this.

I did not used the hardware I2C for several reasons, mainly I don't want hardware I2C support to be a PIC choice requirement.

[BobK]

Hi ErnieM,

I honestly did not know that there was both a hardware and a software I2C setups on PICs similar to serial. But, that's why were here isn't it? To learn! Here I am searching for PICs that have I2C pins when I could have used maybe something different. Thanks for the additional knowledge.

BobK

[mister_e]

HPWM, HSERIN, HSEROUT will use the PIC dedicated pin as it use the internal Hardware module. SERIN/SEROUT/I2CREAD/I2CWRITE/SHIFTIN/SHIFTOUT are a software solution and may be used on almost any i/o of your PIC.

Maybe one day we will have HI2CREAD/Hi2CWRITE/HSHIFTIN/HSHIFTOUT, in the meantime, we used those we spend hours/days/months on.

[BobK]

Thanks Mr E for the education. That's what I like about this place! Always something to learn.

BobK