UART and UARTE peripherals

RE: UART and UARTE peripherals

Simonr — Thu, 27 Jan 2022 07:25:01 GMT

The file you refer to is the legacy nrf_drv_uart.c/.h files, which if from before the UART and UARTE drivers had separate files. In the nrfx drivers we have separate files for UART and UARTE, and it works similar to what Markku describes, where the UARTE and UART is just the peripheral with and without EasyDMA. We generally recommend using the UARTE with EasyDMA as there isn't much extra setup compared to the simple UART, but you're free to use the basic UART if you prefer that.

Best regards,

Simon

RE: UART and UARTE peripherals

danmcb — Wed, 26 Jan 2022 13:56:04 GMT

no, there are separate files, typedefs, everything, for UART and UARTE.

RE: UART and UARTE peripherals

mrono — Wed, 26 Jan 2022 13:53:53 GMT

I think that is just the Nordic uart driver's way of choosing either uart or uarte.

RE: UART and UARTE peripherals

danmcb — Wed, 26 Jan 2022 13:33:41 GMT

there is this though - a flag to turn off DMA use.

/**@brief Structure for UART configuration. */
typedef struct
{
    uint32_t            pseltxd;            ///< TXD pin number.
    uint32_t            pselrxd;            ///< RXD pin number.
    uint32_t            pselcts;            ///< CTS pin number.
    uint32_t            pselrts;            ///< RTS pin number.
    void *              p_context;          ///< Context passed to interrupt handler.
    nrf_uart_hwfc_t     hwfc;               ///< Flow control configuration.
    nrf_uart_parity_t   parity;             ///< Parity configuration.
    nrf_uart_baudrate_t baudrate;           ///< Baudrate.
    uint8_t             interrupt_priority; ///< Interrupt priority.
#if defined(NRF_DRV_UART_WITH_UARTE) && defined(NRF_DRV_UART_WITH_UART)
    bool                use_easy_dma;
#endif
} nrf_drv_uart_config_t;

RE: UART and UARTE peripherals

mrono — Wed, 26 Jan 2022 12:24:35 GMT

The way I look at UART/UARTE is that there is only one peripheral with two different access methods.

If you access the peripheral using UARTE-> -registers, DMA will be enabled automatically. And similarly if you use UART-> -registers, DMA will be disabled.

Both should be fairly equal in terms of complexity for a simple debug uart.