What's the benefit or detracting quality of using either MCP23017 or another ATMEGA328 slave for an expansion board? It seems to me that one benefit of the MCP24017 would be being able to use it with both 5 and 3.3V systems. The downside is there are fewer I/O pins and is need something like the 74HC4051 for analog input expansion if it need it.
Well you can expend the atmega uart spi you got more pio aio. And the programing is done on the same ide, so I would for atmega presonally.
Frédéric_Plante:
Well you can expend the atmega uart spi you got more pio aio. And the programing is done on the same ide, so I would for atmega presonally.
I'm a bit confused by what you mean. Are you saying using the ATMEGA will be easier to program vs the code/library for the MCP?
Well if you are use to atmega, yes. Personally, I would build an AT command set, or something, and make a expension using serial, but every one has his own style.
Ok. Thanks.