This module is the 16 channel IO extension module of the 12C interface, and built in the MCP23017 chip of MicroChip.
Each IO can be arbitrarily configured as input or output, and a pull up resistor can be set, and the interrupt function can be enabled for the IO configured as input. The IO interface has a strong driving capacity, and the current and current can reach 25mA.
MCP23017 is a high-speed IIC interface. It supports the IIC frequency of 100KHz, 400KHz and 1.7MHz.
The chip has 3 address pins, which can be set up for 8 different addresses. So 8 modules can be connected through two IIC buses to achieve up to 128 IO extensions.
The chip has 3 address pins, which can be set up for 8 different addresses. So 8 modules can be connected through two IIC buses to achieve up to 128 IO extensions.

Features
Operating voltage：3.0V-5.5V
Drive chip：MCP23017
Number of IO: 16 (input, output, interruption)
Drive power supply: 25mA1
12C frequency: 100KHz, 400KHz, 1..7MHz
Working temperature: -40 Celsius -125 Celsius
Chip level: Industrial grade
Parallel multiple: Up to 8
Driver: 51 and Arduino