Issue with the receving example code on SX1262

[vasav123]

Describe the bug I'm not sure if this is a bug or I'm missing something. However, when I use the SX1262 module and try to setup a receving example, the begin returns an error code of -20. From what I read on the wiki pages, this error is happening because "User tried to execute modem-exclusive method on a wrong modem." But, I know that the SX1262 supports both Lora mode and FSK mode, and therefore that should just work.

To Reproduce Use the Example code from SX1262_Receive.

Expected behavior I should be able to recevie stuff.

Screenshots If applicable, add screenshots to help explain your problem.

Additional info (please complete):

• MCU: STM32F103RB
• Wireless module type SX1262
• Arduino IDE version 1.8.9
• Library version: latest

Thanks for your help!

[jgromes]

This happens when you try to do something with the LoRa modem while the FSK modem is active (or vice versa) - for example, attempting to change FSK bit rate when LoRa modem is active.

Are you using unmodified receive example?

[vasav123]

Yes, I'm using the examples without making changes.

[jgromes]

Unable to replicate with STM32L452RE, could you enable debug mode (uncomment this line) and post the output?

[vasav123]

[jgromes]

There seems to be no communication from the module. For comparison sake, this is what the output looks like on my side:

08:08:35.977 -> [SX1262] Initializing ... 80    0   AA  
08:08:36.078 -> 96  1   A2  
08:08:36.078 -> 8F  0   A2  0   A2  
08:08:36.112 -> 8A  1   A2  
08:08:36.112 -> 93  20  A2  
08:08:36.112 -> 88  3   A2  16  A2  A   A2  0   A2  0   A2  0   A2  0   A2  
08:08:36.180 -> 2   3   A2  FF  A2  
08:08:36.180 -> 8   0   A2  0   A2  0   A2  0   A2  0   A2  0   A2  0   A2  0   A2  
08:08:36.248 -> 89  7F  A2  
08:08:36.248 -> 11  0   AA  0   1   

What's the wiring? Are you sure the module is working?

[vasav123]

I think so, I tried to use the transmit example with the same pins and that used to work. Also I've tried the example on 2 different boards but neither works. I'm testing to see if the transmit example works right now but for some reason, I'm getting the same error on that example also now.

[vasav123]

in terms of the wiring im using the nucleo F103rb board with the semtech 1262 board which is supposed to work with the Arduino headers

[jgromes]

Since your module always seems to return value 0x00 during SPI transfer, I strongly suspect hardware issue, either in the connection or in the radio itself.

0x00 (as well as 0xFF) is an illegal value for the chip to return, I can add check to the library so that the error code correctly reflects the lack of communication (i.e. return ERR_CHIP_NOT_FOUND instead of ERR_WRONG_MODEM), but that's about it.

[vasav123]

I guess the only way for me to make sure it hardware is to scope it right? Do you have any other ideas?

[jgromes]

That's probably the only way to be sure. You could also unplug the shield and connect only the SPI, DIO1 + 2 and BUSY pins using some jumpers, to make sure there's no additional connection that's causing the issues.

[jgromes]

Closing for now since it doesn't seem like this a bug in the library. Feel free to reopen later.