My initial RAK811 LPWAN Evaluation Board(EVB) test rig was based on an STM32F7691DISCOVERY. I connected the EVB with jumper leads and sent the AT Command to request the LoRaWAN module version information
The STM32F691DISCOVERY board has an Arduino Uno R3 format socket which I wanted to be able to plug the EVB into. After removing R8,R17 & R19 I put the EVB on the STM32F691DISCOVERY and could still retrieve the RAK811 module version information.
The thread '<No Name>' (0x2) has exited with code 0 (0x0). devMobile.IoT.Rfm9x.ShieldSerial starting COM5,COM6 TX: 12 bytes to output stream. TX: 12 bytes via COM6 RXs :19 bytes read from COM6 RX sync:OK V220.127.116.11.H.T3 TX: 12 bytes to output stream. TX: 12 bytes via COM6 RXs :19 bytes read from COM6 RX sync:OK V18.104.22.168.H.T3