How can I add multiple UARTS to the stm3240g-eval?

deckhard · ‎2023-02-13

There is only one RS-232 connector on the stm3240g-eval.

I need all 6 UARTS from the STM32F407IG on board.

Preferably RS422.

Is it possible to use lines from the daughter board connector?

Peter BENSCH · ‎2023-02-16

Of course, you can connect the MCU side of the ST3485EB directly to the UART pins of the STM32: RO to RX and DI to TX, the enable pins can then be controlled by hardware flow control DE. This hardware flow control is possible with some STM32 families, e.g. the STM32F7 or STM32L4.

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Good luck!

/Peter

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Peter BENSCH · ‎2023-02-13

Well, the problem will be to free the port pins of the UARTs/USARTs from already connected functions (FSMC, etc). It is probably best to change to a NUCLEO board, where almost all pins are free to use.

Does it answer your question?

Regards

/Peter

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deckhard · ‎2023-02-13

Yes a NUCLEO would be easier to use but I already have the STM3240G.

Can I re-route the CAN D-type 9-pin connector CN10 to any of the USART pins?

On a different note, is an ST eval board with multiple USARTs (6) D-type connectors available?

Could be for any of the MCUs or MPUs available.

Or do I need to design one myself?

Peter BENSCH · ‎2023-02-13

The EVAL, DISCOVERY and NUCLEO boards are primarily intended for evaluating or developing your own hardware. Due to the limited number of pins, the many peripheral functions can only be accommodated if these functions are multiplexed. EVAL and DISCOVERY boards, some of which have Sub-D sockets, therefore usually have a lot of pins already occupied.

However, NUCLEO boards offer considerably more freedom because the pins are usually completely free, but then there is no Sub-D connected.

But it should not be a problem to connect an RS422 transceiver like e.g. the ST3485EC followed by the Sub-D and thus create as many ports as you want. Could that be an option?

Regards

/Peter

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deckhard · ‎2023-02-14

Does the ST3485EB comes with interface pins so I can connect it easily to the NUCLEO pins?

Peter BENSCH · ‎2023-02-16

Of course, you can connect the MCU side of the ST3485EB directly to the UART pins of the STM32: RO to RX and DI to TX, the enable pins can then be controlled by hardware flow control DE. This hardware flow control is possible with some STM32 families, e.g. the STM32F7 or STM32L4.

If the problem is solved, please mark this thread as answered by selecting Select as best, as also explained here. This will help other users find that answer faster.

Good luck!

/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.