Hi… Thank you for reading.

I am experimenting with some Texas PCF8574's and a pic (16f688). All is good.

My questions;

My outputs are all sinking…i.e. 0's. Is there a way of outputting 1's (Source) when true without using external transistor ?

Although I have managed to read and write to and from the device…. can I split the 8 bits. 4 read and 4 write for example.

Do I aways have to write a 1 to the inputs before a read.

Thank you for reading and understanding.

Andy