IO Port Expansion

Hi,

Which is the best chip for expanding IO ports. MCP23017 or MCP23S17. I did not find an example for MCP23017 under arduino playground. Any guess why?

Thanks Akhil

I don't think many of the smaller Arduinos support SPI? The non-S are better for bit banging. Dwight

dwightthinker:
I don’t think many of the smaller Arduinos support SPI?

No they do. The Uno which can be considered the standard supports SPI.

dwightthinker:
The non-S are better for bit banging.

Again no. Please try and give accurate help.

The MCP23017 has an I2C interface where as the MCP23S17 has an SPI interface. SPI is much faster but uses more pins, the I2C only uses two pins.
Normally I use the MCP23S17 but the internals are identical so anything you can do with the MCP23017 you can do with the MCP23S17, you just talk to it differently.

I did not find an example for MCP23017 under arduino playground. Any guess why?

Probably because it is just the same as the MCP23017. Add a page yourself when you find out.

But there is this:-

Thanks Mike I stand corrected. SPI is not an issue. I'm new to Arduinos. Dwight