STM32WL AFSK

[goshawk22]

I was wondering if the STM32WL supports AFSK. From what I can tell, it doesn't due to the lack of DIO pins. Is this correct?

Thanks, Adam

[jgromes]

STM32WL contains SX126x which does support AFSK transmissions. I don't know what exactly you want to do with it, but it should work.

On a side note, is there a specific piece of documentation that gave you the impression that this is not possible? If so, let us know and we will fix it.

[goshawk22]

I was hoping to use the same approach used for the SX126x module, seeing how the STM32WL contains a SX1262. I don't think the other LoRa modules officially support AFSK either.

https://github.com/jgromes/RadioLib/wiki/SDR-Digital-Modes-Guide

[radiohound]

Hope you find a way, and thanks for the link. I had not seen that before.

[radiohound]

I asked ST support about accessing DIO2, and here is the answer they gave me, plus a PDF explaining the process:

Case#: 00229668
Subject: Any way to access DIO2?
Description:
Hi Walter,

I have put together a detailed summary highlighting several approaches that explain how to insert debug lines. The approach can be either through a HAL SubGHz interface or a project generated via CubeMX leading to another SubGHz project structure.

Please review the entire document before trying to implement any of the approaches.

Be aware, that inserting debug lines can sometimes interfere with code operation. It is sometimes easier to set up the IRQ event and simple toggle a GPIO prior to entering Radio Rx functionality and toggling again after the RxDone IRQ is detected.

I have highlighted a few methods of what you can do.

I was not able to go through the Arduino code, I simply don't have the time allocated however, with a quick scan, you should be able to easily adapt what I am showing to the code.

The PDF is attached to this ticket.

If you still have questions please feel free to reach out. I believe you have everything you need at this time.

I hope this helps.

Regards,

ST MCU Support
Debug Lines Several Methods.pdf

[jgromes]

@radiohound interesting document, thanks for sharing it! I have gone through it, however, I'm not entirely sure this is usable for our case. It effectively shows how to output the internal communication lines (SPI, BUSY etc.) between the SX126x and the STM32 on some externally accessible pins. However, it doesn't really go into much detail as to how this mechanism works and based on the terms used (monitoring, debug probe etc.) my feeling is that this only alows to output the signals, not inject them (which is what we would have to to the DIO2 pin).

[goshawk22]

my feeling is that this only alows to output the signals, not inject them (which is what we would have to to the DIO2 pin).

I think this is the case - I tried setting the pins like described in page 12 and I couldn't get it to work.

[radiohound]

Here is my new question regarding the documentation of accessing DIO2 on the STM32WLE5, and their response this morning:

Hello,

Looking through the documentation, it sounds like this solution is meant for the reading of DIO2, but it’s not clear if I can use it to write to DIO2, which is what I am trying to do. Can I write to DIO2 using these methods?

Thank you,

Walter

Case#: 00229668
Subject: Any way to access DIO2?
Description:

Hi Walter,

to read a DIO, you must first be able to set the DIO. If you are using a built in driver then, much of the DIO write and read is done via the radio_driver.c or radio.c files.

In the documentation that I provided, slides 16, 17, 18 show how to write the DIO in order that it can then be read or directed to a GPIO pin for detailed review.

Slides 19 to 26 provide the order and procedure on how to write the DIO's, set the DIO function to a GPIO pin and at the same time read the status for project requirements.

Also, a direct way, at the register level is as follows:

CmdBuf[0] = 0x03; // clear all 10 irq bits : xxxxxx11 11111111 (MSB)
CmdBuf[1] = 0xFF; // clear all 10 irq bits : xxxxxx11 11111111 (LSB)
if (HAL_SUBGHZ_ExecSetCmd(&hsubghz, RADIO_CLR_IRQSTATUS, CmdBuf, 2) != HAL_OK) Error_Handler();

HAL_NVIC_SetPriority(SUBGHZ_Radio_IRQn, 3, 0); // SUBGHZ Radio Interrupt
HAL_NVIC_EnableIRQ(SUBGHZ_Radio_IRQn);

CmdBuf[0] = (uint8_t)((IRQ_RADIO_NONE>>8) & 0x00FF); // MSB Global IRQ mask
CmdBuf[1] = (uint8_t)(SUBGHZ_IT_TX_CPLT|SUBGHZ_IT_RX_CPLT & 0x00FF); // LSB Global IRQ mask - unmask TXDONE (0x0001) & RXDONE (0x0002)
CmdBuf[2] = (uint8_t)((IRQ_RADIO_NONE>>8) & 0x00FF); // MSB DIO1 mask
CmdBuf[3] = (uint8_t)(SUBGHZ_IT_TX_CPLT & 0x00FF); // LSB DIO1 mask - interrupt on TXDONE (0x0001)
CmdBuf[4] = (uint8_t)((IRQ_RADIO_NONE>>8) & 0x00FF); // MSB DIO2 mask
CmdBuf[5] = (uint8_t)(SUBGHZ_IT_RX_CPLT & 0x00FF); // LSB DIO2 mask - interrupt on RXDONE (0x0002)
CmdBuf[6] = (uint8_t)((IRQ_RADIO_NONE>>8) & 0x00FF); // MSB DIO3 mask
CmdBuf[7] = (uint8_t)(IRQ_RADIO_NONE & 0x00FF); // LSB DIO3 mask
if (HAL_SUBGHZ_ExecSetCmd(&hsubghz, RADIO_CFG_DIOIRQ, CmdBuf, 8 ) != HAL_OK) Error_Handler();

Please refer to the reference manual, RM0453 for further information. In my slides, I have summarized the details of the RM and also provided working functions on how to process the DIO's.

I hope this helps.

ST MCU Support

Please visit ST Customer Support Portal for further information.
Link to access the case:
https://ols.st.com/s/case/500Ty00000NyJnTIAV

Best regards,
ST Customer Support

[radiohound]

And a recent follow up about Arduino:

Case#: 00229668
Subject: Any way to access DIO2?
Description:
Hi Walter,
I just went through the Arduino code/library. It is based upon the HAL SubGHz driver as provided with the STM32WL5/LE5.
The only difference is that it has been compiled for C++.
The information I provided is valid and the calls, I just checked, are within the Arduino library.
You should be able to set the DIO and read the DIO if you follow the file I sent last week.
regards,
ST MCU Support

Please visit ST Customer Support Portal for further information.
Link to access the case:
https://ols.st.com/s/case/500Ty00000NyJnTIAV

Best regards,
ST Customer Support