Raspberry PI – FieldBus CAN/RS485/RS232 add-on board

Despite USB being everywhere, I still use a lot of industrial and embedded interfaces, such as RS232 and RS485 interfaces, in my projects. Legacy equipment especially and even new industrial equipment still use RS232 for programming and monitoring. While RS485 interfaces can still be found a lot in industrial communications such as factory automation.

So with this in mind I felt I needed an Raspberry Pi add-on board to simplify a lot of these connections. So here is the Raspberry PIIO FieldBus add-on board. It is a multi-communications board RS232 or RS485 and CAN Bus interfaces.

rpi_piio_fieldbus1_small
The board uses 3.3V components and is completely voltage compatible with the Raspberry Pi.

The board connects directly to the Raspberry Pi’s SPI to provide CAN Bus communications and also to the UART Rx and Tx to provide RS232 or RS485 communications.

CAN Bus interface uses MCP2515 CAN controller and MCP2551 CAN transceiver IC provides CAN Bus v2.0 A/B at 1 Mb/s. It is connected the Pi’s SPI Interface. Connection is provided via a 3-Way screw terminals.

RS232 interface uses a 3.3V MAX3232 (or Equivalent IC) chip and CTS (GPIO16) & RTS (GPIO17) signals are provided. Connection is provided via an industry standard 9-Way D Connector (Male).

RS485 interface uses 3.3V MAX3485 (or Equivalent IC) chip with DE (GPIO27) & !RE (GPIO22) used to control the RS485 transceiver control signals. Connection is provided via a 3-Way screw terminals to the outside world.

The Raspberry Pi expansion port has only on UART interface available for serial communications. So where both circuits are fitted, only one RS232 or one RS485 interface may be connected to the UART, therefore only one interface can be used at any time.

You can find them on our Tindie store

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