How to wake up ST25RU3993-EVAL board without rts and dtr pins?

[JKSah]

Hello,

I want to use multiple uart to communicate this board to pc. I have successfully established connection between uart1 and pc using only rx and tx pins of uart1 (no handshaking and no dtr/rts pins) using ft232 converter. But this connection only works if somehow manually rts and dtr pins wakes up the board. Can any one tell me how to disable this rts/dtr pin wake up so that board can communicate to pc using only rx/tx. Further more this uart1 pins will be connected to some other communication interface like wifi/lan etc that only have rx and tx.

@Nick K​ Kindly help or any other member kindly help.

Thank You

[JKSah]

@Nick K​ Kindly help or any other member kindly help.

[Nick K · Accepted solution]

Hello,

The EVAL board connects the NRST and BOOT0 pins of the STM32L4 with the RTS and DTR pins of the UART host communication interface.

Please have a look to the schematic of the EVAL board. You can download it at the following location https://www.st.com/en/evaluation-tools/st25ru3993-eval.html#resource

The RTS and DTR line of UART are not needed for communication, just to control the boot behavior of the MCU. It's used to allows a host system to control how the STM32L4 boots up, either in main flash or in system memory to download FW content to the main flash.

If you do not need any bootloader or access it different you can hardwire the BOOT0 pin of the STM32L4 on the EVAL board, the same applies to the NRST pin.

Another possibility for your host system would be to use normal GPIO's instead of of the RTS and DTR lines of the UART interface.

In any case you need to modify the wiring on the EVAL board if you can not control the DTR and RTS pins of the UART.

BR Nick

[JKSah]

Thank You @Nick K​ .