I tested the Seeed Grove LoRa E5 and it worked well. Then I bought a number of Seeed LoRa E5 modules to use on custom boards. I followed the schematic shown in the datasheet but I am unable to get a response from the module. The pins RX and TX are read low (~0.8V) all the time. I modified the circuit on the Seeed Grove LoRa E5 to be identical to the circuit on my custom board. The Seeed Grove LoRa E5 still works as expected but the modules I bought from DigiKey do not respond at all.
My connections are :-
- Vcc → 3.3V
- All GND pins → GND
- RST → pulled up with 10K ohms. Also tried floating
- PB13 → pulled up with 10K ohms. Also tried floating
- PB7 → FTDI TX ( operating at 3.3V)
- PB6 → FTDI RX ( operating at 3.3V)
The module does not respond at all to AT commands. I noticed that the pins RX and TX are low; they measure ~0.8V. I doubt they have the AT commands firmware.
Are they all sold with the AT command firmware?