CMWX1ZZABZ-091 in Sigfox mode

[GErma.1]

The reference design of the CMWX1ZZABZ-091 shows a connection between pins SX1276_DIO4 and PA5/ADC5/DAC2 when in Sigfox mode. The B-L072Z-LRWAN1 board has a jumper between these pins (SB26), but according to table 11 of the manual this jumper is Reserved to LoRa ® / SigfoxTM module debug.

Could please clarify the function of SB26 and SB27? The SB26 and SN27 are mandatory for a custom LoRaWan/Sigfox borad?

BR

Gilberto

[Tesla DeLorean]

The two pins are not physically connected internally, for the module to read the DIO4 pin of the radio chip it must be connected externally. The inference is that the firmware needs this to generate an interrupt, this is why the reference circuit is provided. I'd expect you could scope the pin and confirm this if you doubt, or remove the solder bridge on the Discovery board.

[GErma.1]

Thanks!

Is the internal schematic of the CMWX1ZZABZ-091 module available? Where can I find it?

BR

Gilberto

[Tesla DeLorean]

I don't think Murata publishes this, you would need to ask them.

A few years back I did provide a pin association list for the module, STM32L072CZ and SX1276, and others have provided teardown pictures of the internals.