- last edited on by
Maxime_MARCHETT
I was just wondering if there was a suitable communications shield that I could use for my NUCLEO H753ZI development board, preferrable if I also use the X-NUCLEO-GFX02 LCD Shield on top.
I've looked almost everywhere but there was no single solution for what I wanted:
* RS232 with full handshake support (3T5R)
* RS485 support for both half- and full duplex
* RS422 since this looks very much like RS485 full-duplex
Other nice-to-have features would be fully configurable either by jumper setting or MCU control, various testpoints that are easily accessible, and could handle both 5V and 3,3V input voltage.
Since I couldn't find anything that even came up close to what I was looking for, I thought of designing one myself! :)
What I came up with was a shield that has been build around the TI THVD4431 chip that has support for all three protocols and is easily configurable by selecting corresponding pins to set high or low.
After some tweaks and modifications, I managed to create a board that is about the same size as the NUCLEO H753ZI development board and has all the hardware and features I wanted:
The board is designed to be compatible with the NUCLEO platform, all* functions compatible with both ZIO & Arduino footprint, and still be able to use the LCD shield on top of it.
Selection of protocols, speed, direction termination and switching between half- and full duplex settings for RS485 can be made with multiple 3-pin jumpers or by software override control by the MCU.
The jumpers have a LED indicator to make it visual how the configuration has been set (High=Amber / Low=green).
This is not only showing to the actual jumper setting, but also represents the status when the MCU is overriding the jumper setting.
The communication shield can be placed on top of the NUCLEO H753ZI development board and the NUCLEO shield can be stacked onto the communication shield.
The only exception that the Arduino can't control is the software control of the Rx and Tx LED's. By default they represent the actual data sent by the MCU but are also jumper-configurable to have these LED's controlled directly by the MCU GPIO pins.
Because I also wanted the LCD shield to be used with it, there were not enough spare pins available for the Arduino platform, so when used on Arduino, the Rx and Tx LED's are only hardware controlled.
Other than here on the forum, what would be a good place to show this project to others, and maybe some Maker platforms where I can sell the unused boards I have ordered?
(I only needed two of them, but it was cheaper to make some extra's)
