Use the DMAMUX with SUBGHZSPI_TX (STM32WL55 or STM32WLE)

[SamirDB]

Hello,

First of all, a short text in order to present my problem :

After reading all documents about the STM32WL55 and STM32WLE concerning the SubGhz and DMA, I don't find how can I use the DMA and DMAMUX with SUBGHZSPI_TX.

Furthermore, I'm working on the board NUCLEO-WL55JC1.

My goal and requirement :

In fact, on the board NUCLEO-WL55JC1, I would like to send  as fast as possible a short message trough the Subghz (LoRa) when the button 1 is pressed. So I think the best way is to use the DMA : the button pressed is the trigger, and using the DMA in memory-to-peripheral, in other words, send 3 bytes from memory (0x83 for Opcode of SetTx, 0x000000 for the timeou) to SUBGHZ module via spi interface.

My analysis :

According the RM0461, the table 72 list the assignement of multiplexer inputs to resources. At 47 DMA request MUX input, they is SUBGHZSPI_TX :

My test :

So I used the Ping-Pong example project.

Even if the SubGhz module activate, I don't find any DMA or DMAMUX tab !

And in DMA in "System Core", I wanted to add a DMA with "Request generation Signal" is SUBGHZSPI_TX but nothing in the list !

So, can someone help me?

Where can I find an example project to use the SUBGHZSPI_TX with DMAMUX ?

Thank you.

[STTwo-32 · Accepted solution]

Hello @SamirDB 

For now, there is not any possibility to use the SUBGHZSPI module with DMA. you should use the bare metal implementation included on the SubGHZ/Lora Middleware.

Best Regards.

STTwo-32