There is only a 1-ch UART port on the original Raspberry Pi, once it is used for terminal debugging, no other serial device is allowed. What a poor situation. Now you have 2-ch extra UART, plus 8 programmable GPIOs, just bring this Serial Expansion HAT.

The SC16IS752 is an I2C-bus/SPI bus interface to a dual-channel high-performance UART. It also provides the application with 8 additional programmable I/O pins. This module uses an I2C interface by default, and its device address is hardware configurable by A0 and A1.

Features:

• Standard Raspberry Pi 40PIN GPIO extension header, supports Raspberry Pi series boards
• Onboard SC16IS752, expands 2-ch UART and 8 programmable GPIO through I2C, no extra pin required
• It is stackable up to 16 this module by setting the address jumper, which means up to 32-ch UART
• Onboard multi LEDs for indicating the UART working status
• Reserved I2C control pins, allows working with other control boards
• Comes with development resources and manual (examples in C and python)

Package Includes:

• 1 x Serial Expansion HAT
• 1 x RPi screws pack (2pcs)
• 1 x PH2.0 6PIN wire