Inter SPI time

[JIYEON]

Hello, 

I wish to send SPI message by 2 Bytes per once, total 102 bytes.

Basically SPI works fine.

I wonder if there is way to reduce inter SPI time. It measured 18u sec.

Could it be around 2 u sec?

Below is my source code. 

nbBYtes is 102. TxBuffer and RxBuffer is 102 size buffer.

    for(index = 0; index < (nbBYtes / 2); index++)
    {
        spi1_xfer_done = false;

        err_code = nrf_drv_spi_transfer(&m_spi_ntm, &TxBuffer[2 * index], 2, tempRx, 2);
        RETURN_IF_ERROR(err_code);

        while (!spi1_xfer_done)
        {
            __WFE();
        }

        RxBuffer[2 * index] = tempRx[1];
        RxBuffer[2 * index + 1] = tempRx[0];
    }

[Sigurd]

Hi,

You could try using array list to improve this.

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/spim.html#topic

[JIYEON]

Hi,

I tried array list. Still 18u sec takes between SPI.

Regarding Easy DMA, I have some questions.

In my configuration, SPI0_USE_EASY_DMA is already enabled.

I defined  Tx&Rx buffer as Array list. 

#define BUFFER_SIZE  2

typedef struct ArrayList
{
    uint8_t buffer[BUFFER_SIZE];
} ArrayList_type;

ArrayList_type gau8TxData[NB_16BIT_XFERS] = {0};
ArrayList_type gau8RxData[NB_16BIT_XFERS] = {0};

and execute SPI communication like below.

        for(index = 0; index < (nbBYtes / 2); index++)
        {
            spi1_xfer_done = false;

            err_code = nrf_drv_spi_transfer(&m_spi_ntm, &gau8TxData[index], 2, &gau8RxData[index], 2);
            RETURN_IF_ERROR(err_code);

            while (!spi1_xfer_done)
            {
                __WFE();
            }
        }

But I can't find .MAXCNT nor .PTR which is specified in your link.
Did I miss something?

[Sigurd]

Hi,

The list feature is enable by the driver when the POSTINC flags are set.

See this page on how to use the driver in advanced mode: 

https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.0.2/hardware_driver_spi_master.html#hardware_driver_spi_advanced