UART/Serial Port Emulation over BLE example doesn't receive over UART (only transmits)

[KSV]

I successfully compiled and loaded the UART/Serial Port Emulation over BLE example on an AdaFruit Feather board.

I can connect to the Nordic UART Service, then send data from the nRF Connect app (Rx Characteristic) to the Feather board (nRF52832) and see the data go out the Feather/nRF52832 UART and into my UART USB dongle and appear on the Linux minicom terminal.

What doesn't work is:

1) I never see the "UART started!" string when the application first starts.

2) I type characters (with newline) on the Linux minicom terminal and I can see on the oscilloscope data on the Feather/RF52832 Rx line, but the application never sees an RX data interrupt fire, and therefore never sends the characters across BLE to the nRF Connect app.

Ubuntu Linux 16.04.6 LTS

S132 SoftDevice v7.0.1

Nordic SDK v16.0.0

(Downloading 'ble_app_uart_pca10040_s132.elf' to J-Link)

[KSV]

I found the problem. It was with the Adafruit setup. The JLink USB was enumerating as a serial port so I had two serial ports: the UART to the Tx and Rx pins on the Adafruit board, and the JLink USB. When the UART Rx wire was connected properly it would conflict with the JLink USB and the board would never trigger a RX interrupt.

I solved the problem by using an nRF52 DK board and all is well with the UART now (the USB/JLink connection enumerates as a USB ACM device so it does not conflict with the UART).