nrf52832 Uart SDK14

[T_chapelle]

Context : I am using a nrf52832 to communicate via UART to a STM32 on a custom board. I've based my work on the Ble nus service example. Main change from the DK is that i don't have an external 32khz so i enabled NRF_CLOCK_LF_SRC_RC

I recently updated the nrf52832 code from SDK12/s132 version 3.0 to SDK14 /s132 version 5.0 because i had issues with some Android devices.

Problem : The BLE part is doing fine now with all the devices that were causing trouble (advertisement, connection, characteristic reading/writing) but the UART part is now unstable.

Hardware flow control is enabled UART_DEFAULT_CONFIG_HWFC, baudrate is set to 115200. On the SDK14, i've tried UART_EASY_DMA_SUPPORT but it's not working, so i switched to using UART_LEGACY_SUPPORT.

At first, uart communication is good at transmitting / receiving but after a while, the connexion hang and i have to reset the whole board. The uart_event_handle doesn't seems to have a APP_UART_COMMUNICATION_ERROR or APP_UART_FIFO_ERROR event but what happen is a high state on the CTS pin of the nrf52. Also, UART_RX_BUF_SIZE value seems to change the delay/latency after which i have this problem.

After debugging i did get those two info from the uart :

EVENTS_CTS 1 EVENTS_NCTS 1 EVENTS_ERROR 0 ERRORSRC 0

Can someone give me hints on what to look after ?

(already saw devzone.nordicsemi.com/.../ and checked the pinout)

EDIT: the high state is on the RTS pin of the nrf52 not the CTS (blue line is RTS, yellow is RX)

[Sigurd]

Hi,

Have you tried debugging, and seeing if you are running into the error-handler ? See this post on debugging.

[T_chapelle]

Yes i tried debugging and everything else is working fine (BLE, leds, buttons), the app is not running into the error-handler.

[Sigurd]

The CTS pin is a input pin for the nRF52, and if the pin is high, then the STM32 is the one setting this pin high. Indicating to the nRF52 that the STM32 is not ready to receive any data.

[T_chapelle]

My mistake, it's the RTS pin that stay high (sorry for that)

[T_chapelle]

Further investigations : i added a app_timer and when it expire, called the following functions : app_uart_flush(); app_uart_close(); uart_init(); // as in ble_app_uart example

After that the uart communication is back for a while, but when i do some ble transfer, it fail again and I can see the RTS line held high before the timer expire.