I'm currently working on a project that will be based on a Nano. all of it's I/O exchange are going to be over I2C. That Nano will be Master over I2C. It will have:
2 x Slave Nano, that will receive 3 bytes of info, every 250 mSec, is fine 4 x PCF8574 IO expander, that will receive 1 byte (all outputs) of info each. Every 250 mSec is fine 1 x PCF8574 IO expander, that will send 1 byte (all inputs) of info. every 250 mSec is fine 2 x PCF8574 IO expander, that will send 1 byte (all inputs) of info. This ones, I need fairly fast (50 mSec)
any of you foresee throughput issue ?
I saw the following post: http://forum.arduino.cc/index.php?topic=16793.0
It explains how to switch to 400KHz I2C speed. Will I need to go that fast or the 100KHz base speed shall be enough ?