RE: Is there any UART examples by directly accessing the registers?

Jared — Tue, 25 Jun 2019 12:36:06 GMT

Hi,

The sample codes shows only how to transmit. I suggest that you read the UARTE Receive chapter to understand how you should implement the reception.

regards

Jared

RE: Is there any UART examples by directly accessing the registers?

Hansome — Tue, 25 Jun 2019 01:19:57 GMT

Thanks! But where is the receiving interrupt?

RE: Is there any UART examples by directly accessing the registers?

Jared — Mon, 24 Jun 2019 10:55:29 GMT

Hi,

There isn't one available in the SDK for UART but here is one for UARTE for nRF52840:

#include <nrf.h>

#define PIN_TXD        (6)
#define PIN_RXD        (8)

int main(void)
{
  uint8_t hello_world[] = "Hello World!\n";
  
  // Configure the UARTE with no flow control, one parity bit and 115200 baud rate
  NRF_UARTE0->CONFIG = (UART_CONFIG_HWFC_Disabled   << UART_CONFIG_HWFC_Pos) |
                       (UART_CONFIG_PARITY_Included << UART_CONFIG_PARITY_Pos); 
  
  NRF_UARTE0->BAUDRATE = UARTE_BAUDRATE_BAUDRATE_Baud115200 << UARTE_BAUDRATE_BAUDRATE_Pos;
  
  // Select TX and RX pins
  NRF_UARTE0->PSEL.TXD = PIN_TXD;
  NRF_UARTE0->PSEL.RXD = PIN_RXD;
  
  // Enable the UART (starts using the TX/RX pins)
  NRF_UARTE0->ENABLE = UARTE_ENABLE_ENABLE_Enabled << UARTE_ENABLE_ENABLE_Pos;
  
  // Configure transmit buffer and start the transfer
  NRF_UARTE0->TXD.MAXCNT = sizeof(hello_world);
  NRF_UARTE0->TXD.PTR = (uint32_t)&hello_world[0];
  NRF_UARTE0->TASKS_STARTTX = 1;
  
  // Wait until the transfer is complete
  while (NRF_UARTE0->EVENTS_ENDTX == 0)
  {
  }
  
  // Stop the UART TX
  NRF_UARTE0->TASKS_STOPTX = 1;
  // Wait until we receive the stopped event
  while (NRF_UARTE0->EVENTS_TXSTOPPED == 0);
  
  // Disable the UARTE (pins are now available for other use)
  NRF_UARTE0->ENABLE = UARTE_ENABLE_ENABLE_Disabled << UARTE_ENABLE_ENABLE_Pos;
  
  while (1)
  {
    __WFE();
  }
}

regards

Jared