MCP23016 I/O expander

[Demon]

Robert,

I'm sorry, this still doesn't make any sense to me.
Why use opto's when you aren't isolating anything?

Ralph,

The optos were used only as a means of being able to switch between more than 8 MCP23016. I can easily activate the MCT6 I wish with a single pin from the PIC. Don't look for any fancy reasons, there aren't any.

It was the only idea I could come up with the have more than 8 MCP23016 share a common SDA line (since I don't know how to have more than 1 SDA line per PIC).

Robert

[Demon]

Awe ben tabarnoune!

Ralph, one of your comments made it seem like all I had to do was to use another pin as an SDA and just go on from there. So that's what I just tried and the darned thing works!

Ok, that's great. But why is the SDA line listed on a particular pin on the 16F877 datasheet?

I thought that since it was listed on RC4 that THAT was the only place it would work. Hence why I tried all these acrobatics to work with this limitation.

This brings up another question; will SDA work on all pins?

Robert

[Demon]

Ok, just saw your post come up.

Thanks very much Ralph and Melanie.

I was going to say thanks to that Mister_E comedian, but he's ignoring my emails. :P

Robert

[mister_e]

Dear vieux debris
Glad to see that there's some light up your head now. I2CWRITE/I2CREAD/SHIFTOUT.... SERIN/SEROUT... will work on any I/O since it's a software solution as Ralph said. It isn't the same as HSEROUT and HPWM wich use the specific PIC i/o.

The beauty of PBP against another Basic compiler is that you can use/do as many I2C bus as you have free I/O. Hey, even if we still heard here and there that PBP is a dead/dummy/..../...../..../ language, it's still usefull

Usually i don't share SCL line between I2C buss... kind of personnal safety feeling i guess... but it's working.