BG95-M2 Main-UART not working

IoT Modules LPWA Module
1

Hi all,

I’m currently testing a selfmade PCB using a BG95-M2 module.
It works almost as expected when using the USB interface.
I can send AT commands and get an answer.

But the main application is to control everything via UART through a microcontroller and this does not work at all.
By using an oscilloscope I can’t see any signal activity on MAIN_TXD.

I tried a BG95-M3 Module before and immediately after power-up it outputs “RDY” and “APP RDY” on the UART.
I thought -M2 und -M3 should behave exactly the same, but it seems it does not.
The -M2 version is also active (CFUN=1) immediately after power-up, while the -M3 is not.

Output of BG95-M2 via USB after power-up:

RDY
+CFUN: 1
+CPIN: READY
+QUSIM: 1
+QIND: SMS DONE
APP RDY

ATI

Quectel
BG95-M2
Revision: BG95M2LAR02A04

AT+QGMR

BG95M2LAR02A04_01.003.02.003

Output of BG95-M3 via UART after power-up:

RDY
APP RDY

ATI

Quectel
BG95-M3
Revision: BG95M3LAR02A03

Schematic

grafik
grafik1683×1053 122 KB

Any ideas ?
Do I need a different firmware ?

Best regards,
lakeroe

2

It seems that RTS and CTS are floating. Maybe you can short them to the GND.

3

Hello,

in the meantime I ordered and tested another BG95-M2 module and I think I found the problem.

Working BG95-M2 module

AT+QGMR
BG95M2LAR02A04_A0.301.A0.301

NOT Working BG95-M2 module

AT+QGMR
BG95M2LAR02A04_01.003.02.003

The hardware setup for both modules is exactly the same, so the only difference is the firmware.
Can you please send me the firmware of the working module, so I can update the none-working one and confirm this issue ?

Many thanks,
lakeroe