Testing MCP23018 i2c io expander

Rayman

Found a driver for MCP23017, which is very similar, so testing it out with MCP23018.
(Thanks Jon!)
Arguably, should have used ...017, but liked the high speed and high current of ..018

Might pay for this decision by needing some extra pull-ups on some I/O
There are internal pullups, but they are kind of weak at 100k...

Anyway, Jon's ...017 object seems to work just fine with ..018.
Guess the one difference is that one must turn on pull-ups to see I/O actually change since ..017 is push-pull, but ..018 is only pull...

This test is without crystal, so guess RC fast mode (? don't remember), but works anyway...

Rayman

Aside: Was driving me crazy at first because none of the outputs were working.
But, found a tiny solder bridge between pins #16 and #17. Kind of strange that would lock out output, but there it is...