UNOR4 AT USART #9
Description
The main MCU has an additional usart connection (SCI1) to the USB bridge MCU (ESP32). The bridge is also running an AT command service that provides an interface to the WIFI/BLE capabilities of the ESP32.
There is an initial prototype of the AT-USART on main, largely copying what was done for the usart connection bridged to the USB port (SCI9). However it is not working yet. The TDRE flag (transmit data register empty) flag is never coming on for some reason. This flag signals that data has been transferred from the data register to the shift register for transmission (in non FIFO mode).
Need to get the AT-UART working and run some initial AT command tests to confirm it is ready for use.