RS485 / RS422 shield for Raspberry Pi

a professional RS422 / RS485 shield with many options

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This is a professional RS422/RS485 HAT for the Raspberry Pi. I wasn't satisfied with the shields on the market. They are very simple and have some disadvantages.

 My RS485 HAT comes with the following features:
- RS422 (full duplex) support
- RS485 (half duplex) support
- galvanic isolation between PI and interface
- indicator leds for RX and TX activity
- switchable pull-up, pull-down and terminal resistor
- different modes for send/receive switching (Auto, GPIO, always transmitter, always receiver)
- Auto switching via monoflop
- all options adjustable via DIP switches
- removable bus terminal

Application Note ModBus Rev A.pdf

How to use MODBUS RTU with this RPI HAT

Adobe Portable Document Format - 126.48 kB - 08/29/2018 at 09:20


Application Note DMX512 Rev C.pdf

How to use DMX512 and RDM with this RPI HAT

Adobe Portable Document Format - 226.87 kB - 01/15/2018 at 13:27


RPI_RS485 Schematic V01-01-00.pdf


Adobe Portable Document Format - 210.91 kB - 09/01/2017 at 16:35


Datasheet RS485 shield Rev A.pdf

Datasheet and DIP switch configuration

Adobe Portable Document Format - 221.51 kB - 09/01/2017 at 16:34


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avdm wrote 04/04/2019 at 14:35 point

There is a major issue with the hat: the print on the pcb for the terminal block connector A and B should be switched; took me while to figure out, but found the issue when I looked into your schematics at . The print for pin 1 on the terminal should be B and for pin 2 should be A.

Switching the cables (e.g. A to B and B to A) solved the issue for me.

For reference, I have board version 01-01-00

  Are you sure? yes | no

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