We are using a Murata CMWX1ZZABZ-072 module with an STM32 embedded micro and Semtech SX1706 which uses the I-CUBE-LRWAN expansion. Question - how do I tell the SX1706 to switch to US915 band, sub-band 2? IS there an AT mdem command for this?

[TZarn.1]

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[Tesla DeLorean]

SX1276

There should be a command line build option, REGION_US915

If that's not sufficient review the code for the table holding the frequency plan.

The AT commands will be listed/implemented in the code also.

[TZarn.1]

HI, yes, that I have, the US915 contains 64 125kHz wide channels. However most Gateways only receive 8 of those channels within each sub-band, of which there are 8 sub bands within US915, Most Gateways allow us to select which sub-band to use, for example sub band 2. However that module is using all 64 channels, so it sends data randomly on 64 channels while the Gateway is only listening on 8 of them - lots of missed messages....Back t the question, Ido not see an obvious way of selecting a sub band within the I-CUBE-LRWAN package using an AT command, or is there a way?

[Tesla DeLorean]

I don't believe there is an AT command to do that, but you have ALL the source

Check the frequency plan here, adjust/expand as desired

STM32CubeExpansion_LRWAN_V1.3.1\Middlewares\Third_Party\LoRaWAN\Mac\region\RegionUS915.h

STM32CubeExpansion_LRWAN_V1.3.1\Middlewares\Third_Party\LoRaWAN\Mac\region\RegionUS915.c

For a more complex template, look at

STM32CubeExpansion_LRWAN_V1.3.1\Middlewares\Third_Party\LoRaWAN\Mac\region\RegionEU868.h

STM32CubeExpansion_LRWAN_V1.3.1\Middlewares\Third_Party\LoRaWAN\Mac\region\RegionEU868.c

[TZarn.1]

Thank you fro the info, we'll give it a go.

[Tesla DeLorean]

As this is derived from the Semtech stack, you might look to see if anyone has created a more complex/refined version already.

[TZarn.1]

RESOLVED: Changed the end node to use US915_HYBRID, turn off Automatic Data Rate (AT+ADR=0) and set the Data Rate to 4/5 (AT+DR=4). Set Gateway to receive on sub Band 1 which is the lower 8 125kHz channels. This also set the Spreading factor to 10 (SF10). Now join request happen on the first attempt and so far all messages are received.

Thank you!