A maximum of 8 of these modules can be daisy-chained to a maximum of 64 digital IO.
8 different I2C addresses can be selected after a small modification:
The I2C address on these modules is fixed by default, but it can be changed by cutting the 3 short traces shown in the picture and adding jumper caps instead.
The modules contain 10k pull-up resistors for the I2C bus. Please understand that these resistors will be connected in parallel when you cascade multiple modules.
The library for Arduino is available.
Supply voltage: 2.5 – 6V
Max. combined current: 100mA
Output current source: 1mA max.
Output current sink: 25mA max.