ProMini extender explained

[kolin]

Hi,
Thanks for great project. It is most polished solution for ESP ever.

I need more IO on my node. I do not have i2c port expander. But I have plenty of Atmega328. I like to use them.
"ProMini expander digital" option is almost self-explaining, but where can I find sketch for for AVR?
Peeking at source code revealed it is working like i2c slave, clever

[Martinus]

AVR code exists and works. But it does have a strange bug with collecting data on the I2C bus. Currently it can only receive one byte. Sending more than one byte is no issue. This puts a small limitation on current usage. The analog data is read with 'value/4' so the range is 0-255 where the ADC on Atmel is actually 10 bits and ranging from 0-1023. I would like to get this fixed but a bit lack of time...

I will add the Pro Mini sketch to github so you can have a try with it. It should work with plain digital port read/write and analog port read/write (8 bits limitation).