[TriEmbed] Raspberry Pi & Port Expanders

[Grawburg]

as many of you already know I'm a big fan of using an I/O port expander (MCP23017 or MCP23008) when I'm working with anything that uses voltage other than 3.3 VDC. I want to make sure the Pi is fully isolated from the devices.  I realize that the Python coding is a bit more involved when using an I2C device and that it doesn't currently run on Python 3. I just think the trade-off with protecting the Pi is worth it.  Now, here's my question: Is there a situation when I should not use an I2C chip, keeping in mind the projects I'm dealing with are, by most standards, relatively basic?

At tonight's meeting I'll have part of my pipeline valve and pump project that is using a single MCP23017 because I need more than 8 I/O pins. If there is an interesting alternative to the I2C I'd like to know about it.


Thanks,
Brian Grawburg