2-Channel Isolated RS485 Expansion HAT for Raspberry Pi



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 the SPI interface. Due to its fast communication, stability, reliability, and safety, it is an ideal choice for fields like industrial automation.


  • 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, lightning-proof & 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)


  • 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

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



VCC5V3.3V/5V power supply
SCKP21 (SPI1 SCLK)SPI clock input
MOSIP20 (SPI1 MOSI)SPI data input
MISOP19 (SPI1 MISO)SPI data output
CSP18 (SPI1 CS)SPI chip select
IRQP24Interrupt output
EN1P27Channel 1 TX/RX enable: high for TX, low for RX
EN2P22Channel 2 TX/RX enable: high for TX, low for RX


Part List

  1. 2-CH RS485 HAT x1
  2. 2x20PIN female pinheader x1
  3. RPi screws pack (2pcs) x1



Source: 2-Channel Isolated RS485 Expansion HAT for Raspberry Pi

About The Author

Muhammad Bilal

I am highly skilled and motivated individual with a Master's degree in Computer Science. I have extensive experience in technical writing and a deep understanding of SEO practices.

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