UART Hardware Flow Control

[maveli]

Hello Nordic community,

using nrf5-sdk for nrf52840 SoC, I followed the uart example as below.

ret_code_t uart_init(void)
{
	ret_code_t err_code = NRF_SUCCESS;
	
	app_uart_comm_params_t const comm_params =
	{
		.rx_pin_no    = U_RX,
		.tx_pin_no    = U_TX,
		.rts_pin_no   = U_RTS,
		.cts_pin_no   = U_CTS,
		.flow_control = APP_UART_FLOW_CONTROL_ENABLED,
		.use_parity   = false,
		.baud_rate    = NRF_UART_BAUDRATE_76800
	};

	APP_UART_FIFO_INIT(&comm_params,
                		 RX_BUF,
                		 TX_BUF,
                		 uart_event_handle,
                		 APP_IRQ_PRIORITY_HIGH,
                		 err_code);
	
	return err_code;
}

The uart tx and rx works fine BUT NOT THE HWFC 

eg. When the CTS is set HIGH, the transmitter (nRF52840) doesn't stop sending.

      (I tried setting the CTS to LOW as well, but no change in the transmitter behavior)

So my questions are:

1. Why this simple test for Hardware flow control over UART is not working?

2. Is there any example that you can provide for UART with HWFC, where the nRF as Transmitter reacts to CTS?

Thank you for your support.

Best regards.

Lal