Hi,
> - are the pins 'provided' by an extender as usable as normal GPIO pins (for instance to connect and LCD, or a cascaded extender)?
Coincidentally, the example described previously with the HD44780 driver over an I2C IO-expander is now officially an example.
https://github.com/roboterclubaachen/xpcc/blob/develop/examples/stm32f4_dis…
Cheers,
Niklas