Using two UARTs on nrf52833.

RE: Using two UARTs on nrf52833.

Vidar Berg — Thu, 10 Sep 2020 10:10:10 GMT

Hello,

Are you testing this on the nRF52833 DK, or a custom board? I noticed from the silkscreen on the backside that P1.00 is connected to the SWO input on the Segger interface chip. Maybe that's what's causing the interference.

Solder bridge configuration:

SB57

Closed

Cut to disconnect the nRF52833 SWO line from the signal switch and the interface MCU

RE: Using two UARTs on nrf52833.

Nikolay Oleynik — Wed, 09 Sep 2020 10:55:26 GMT

Hello.

I don't use flow control.
1) OK, I have UARTE0 and UARTE1.
2) When UART is initialized on port 1, many interrupts with an error are immediately called. Moreover, if you call nrf_drv_uart_rx () again in the interrupt, then this function hangs. If we initialize UART to port 0, then everything will be without errors. Unfortunately, schematically, it is necessary to use 24 pins on port 0 for sending and 0 pin on port 1 (32 pins) for receiving.

Yes, I am using the NRF_GPIO_PIN_MAP (1, 0) macro

RE: Using two UARTs on nrf52833.

Vidar Berg — Tue, 08 Sep 2020 11:19:09 GMT

Hello,

Are you testing with HW flow control enabled, and in that case, have you connected the RTS and CTS line? Incorrectly configured flow control could potentially explain why you never get the TX complete event.

1) There is no legacy UART1 without DMA as you say, so you need to use the UARTE driver (UART doc).

2) Induced noise on a floating RX input may be enough to trigger a NRF_DRV_UART_EVT_ERROR. Have you tried to ignore the error and just re-enable UART RX ((void)nrf_drv_uart_rx()) on this event to see if any data comes trough at all.

Also, do you use the NRF_GPIO_PIN_MAP() when specifying pins on port 1? e.g., NRF_GPIO_PIN_MAP(1,0) => p.1.0