I am struggling to configure my MCP23017 with pure cmd line calls from
i2cset and i2cget on the lastest Raspberry Pi 4.
Since this is an requirement to use pure cmd line calls, neither C or
Python or whatever API is allowed.
What I have done so far:
Device has an I2C address like: 0x20
i2cset -y 1 0x20 0x00 0xff
Set all pins from PORT A to inputs.
i2cset -y 1 0x20 0x02 0xff
enabled it for all pins
i2cset -y 1 0x20 0x03 0x00
set the default compare register to 0 because I want to trigger an INT if value changes to 1 on input pins
i2cset -y 1 0x20 0x04 0x00
mhmm I am bit lost already - would think that this must also bei 0x00 for all pins?!
BUT if I change the logical level on the pins from PORT A (all pins are
set to active low by external resistor) from LOW to HIGH (and vice
versa) nothing is happening.
I don't know why - has anyone an idea what I am doing wrong here?