How to define and use UART & TWIS without DMA transmission on nrf52810?

[studzinski]

I would like to use my nrf51 applications working without DMA on nrf52810.

In nrf52810_peripherals.h there is no such settings.

When defined "manually", the project does not compile.  Error: "NRF_UART_Type" is undefined

My main file functions  (from example  given by Petter Myhre):

#include "nrf.h"
#include "nrf52.h"
#include "app_uart.h"
#include "nrf_uart.h"
#include "app_error.h"
#include "nrf_delay.h"
#include "boards.h"
#include "app_error.h"

void uart_error_handle(app_uart_evt_t * p_event)
{
    if (p_event->evt_type == APP_UART_COMMUNICATION_ERROR)
    {
        APP_ERROR_HANDLER(p_event->data.error_communication);
    }
    else if (p_event->evt_type == APP_UART_FIFO_ERROR)
    {
        APP_ERROR_HANDLER(p_event->data.error_code);
    }
}



void uart_init()    
{
    uint32_t err_code;
  const app_uart_comm_params_t comm_params =
    {
        RX_PIN_NUMBER,
        TX_PIN_NUMBER,
        RTS_PIN_NUMBER,
        CTS_PIN_NUMBER,
        APP_UART_FLOW_CONTROL_DISABLED,
        false, // no parity
        //UART_BAUDRATE_BAUDRATE_Baud9600
        UART_BAUDRATE_BAUDRATE_Baud115200
    };
    APP_UART_FIFO_INIT(&comm_params, // UART unique initialisation macro
        32, //UART_RX_BUF_SIZE in bytes
        512, //UART_TX_BUF_SIZE  in bytes
        uart_error_handle, // callback function address
        APP_IRQ_PRIORITY_LOW,
        err_code); // error code output is put in error_code variable by macro      
    if (err_code!=NRF_SUCCESS)
        ;
        //quick_blink(); // optical error alert
}    
   

[Jakub Rzeszutko]

Hi,

For peripherals like UARTE, TWIM, TWIS, SPIM, SPIS EasyDMA is the only possible transfer option.

[ovrebekk]

And to add to Jakub's reply, the nRF52810 does not have the older UART, TWI and SPI interfaces. 

They were kept around in the nRF52832 for compatibility reasons, but have now been deprecated in new designs. There is no benefit to using the non-DMA versions over the DMA versions, other than being able to use old code without modifications. 

[studzinski]

Thanks for the confirmation.

The post of Jakub saddened me very much, because we have developed our product for nrf51822 without DMA feature and changed the chip thinking that it is 100% software compatible...

Have you any example of use of UARTE? The example I have is obviously for UART, not for UARTE.

Will it work "as is"?  If no, what modification is necessary to make working using app_uart_fifo.c library?

Is this library "transparent"?

Idem for TWIS...

Cordially

[Jakub Rzeszutko]

Hi,

Some example how TWIS peripheral can be used you can find here:

sdk\nrf5\examples\peripheral\twi_master_with_twis_slave

Basically peripherals with EasyDMA are using memory buffer for Tx and Rx data. If you will set size of these buffers to 1 byte you will be more less using UARTE/TWIS like UART/TWI peripherals.

There are some other event flags you need to look for, but this can be found in the documentation.