We have developed a custom board based on an eval board that has a LoRa transceiver and an RFID tag reader connected to two UARTs of the MCU. A serial console is also connected to a third UART. DMA streams are configured for the LoRa and RFID UARTs, and for Ethernet. The software application uses FreeRTOS and has an Ethernet stack implemented using LwIP. The app responds to UDP commands received by the device, which trigger interactions with the LoRa or RFID devices.
The application works as expected when a USB J-Link JTAG interface is connected to the board, whether using the debugger, or just running. However, if the board is powered on without the USB J-Link attached, Ethernet does not work. The board does not receive any UDP packets or even respond to pings. The LEDs still flash, indicating that the main thread is still running.
Any suggestions?
