# RS485 Expansion HAT for Raspberry Pi - 2-Channel Isolated

**Type:** Product page · **SKU:** WS-17221 · **Brand:** [Waveshare](https://core-electronics.com.au/brands/waveshare-in-australia)
**Page:** https://core-electronics.com.au/rs485-expansion-hat-for-raspberry-pi-2-channel-isolated.html ([markdown](https://core-electronics.com.au/rs485-expansion-hat-for-raspberry-pi-2-channel-isolated.html.md))

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.

## Pricing

- **Price:** $31.85 (inc GST) — $28.95 AUD, exc GST
- **Quantity discounts:** 10+ $27.80 (exc GST) · 25+ $26.93 (exc GST)

## Availability & dispatch

- In stock, ships same business day if ordered before 2PM (Australia/Sydney).
- We can dispatch 8 today, and up to 300 more in 12–19 days.

## Description

Featuring a standard Raspberry Pi 40PIN GPIO header, it utilises a combination of the SC16IS752 and SP3485 chips to convert SPI to RS485, allowing for data transfer rates of up to 921600bps. Users can transceive data both manually and automatically, depending on their configuration. The board also includes an onboard TVS (Transient Voltage Suppressor) that mitigates surge and transient spike voltages. There is also an onboard auto-recovery fuse and protection diodes as an added layer of device protection.

Note: *This product does not come with mounting hardware.*

## 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

**![Diagram](https://core-electronics.com.au/media/wysiwyg/product_info/ce07311-diagram.jpg)**

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
 
## Documents

- [Wiki](https://www.waveshare.com/wiki/2-CH_RS485_HAT)

## Images

- [Product image 1](https://core-electronics.com.au/media/catalog/product/c/e/ce07311-1.jpg)