Arduino library for the 40bit PCA9505/06 I2C IO Expander
These chips use I2C to communicate, and have interupt, reset and output enable controls. A 3bit configurable addressing is supported ranging from 0x20 to 0x27 enabling upto 8 40bit IO on one bus.
The PCA9505 has internal 100k pullup resistors where as the PCA9506 does not. This is the only difference between the 2 chips.
The chip operates between 2.3v and 5.5v. All IO are 5.5v tolerant.
All IO are defaulted as inputs on power on.
Output enable disables outputs on ALL IO configured as outputs and could be used to send an PWM signal to dim LED's connected to outputs.
Interupt is active LOW when a pin's state has changed.
My IO Expander board design is available on EasyEDA here: https://easyeda.com/tofuman/40bit_GPIO_Expander_Board-ca14a80c34f64675b12a7c6f5bcb47ed