This is a 2-channel isolated RS485 expansion HAT designed for Raspberry Pi, adopts the SC16IS752+SP3485 solution, with embedded protection circuits such as power supply isolation, ADI magnetical isolation, and TVS diode, etc.

It is easy to control the 2-channel RS485 for auto transceiving via SPI interface. Due to its fast communication, stability, reliability, and safety, it is an ideal choice for fields like industrial automation.

Features

• Standard Raspberry Pi 40PIN GPIO extension header, supports Raspberry Pi series boards
• Adopts SC16IS752+SP3485 dual chip combination, converts SPI to RS485, data rate up to 921600bps
• Allows transceiving data manually or automatically, configured by DIP switch
• Onboard TVS (Transient Voltage Suppressor), effectively suppress surge voltage and transient spike voltage in the circuit, lightningproof & anti-electrostatic
• Onboard auto-recovery fuse and protection diodes, ensures the current/voltage stable outputs, provides over-current/over-voltage proof, improves shock resistance
• Onboard LEDs for indicating the power and transceiver status
• Breakout SPI control pins, for connecting with host control boards like Arduino
• Comes with development resources and manual (examples in C and Python)

Specifications

• UART expansion chip: SC16IS752
• RS485 transceiver: SP3485
• Communication interface: SPI
• Data rate: 300 ~ 921600 bps
• Operating voltage: 3.3V / 5V
• Dimensions: 65mm × 56.5mm
• Mounting hole size: 3.0mm

What's on Board

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1. SC16IS752 UART expansion chip
2. ADUM1412 digital isolator
3. PC817 optocoupler
4. SP3485 RS485 transceiver
5. B0505LS power supply isolation module
6. RT9193-33 power chip
7. SMAJ12CA transient suppress diode array
8. Auto-recovery fuse
9. Status indicator
   PWR: power indicator
   RXD/TXD: UART transceiving indicator
10. Raspberry Pi GPIO connector: for connecting Raspberry Pi
11. RS485 terminal
12. MCU control header: for connecting host control boards like Arduino
13. 120Ω terminal resistor switch
14. Interrupt pin switch
15. Operating mode selection
    Half-auto: A=0, B=1
    Full-auto: A=1, B=0

Resources

• Wiki - 2-CH RS485 HAT