[NRF52810] SPI (without DMA) 's SCK signal isn't continuous

[Triumph]

hello,

I use the SPI demo in the Official SDK.

but the SPI's SCK signal has a break every bytes,

why?

[Kenneth]

Hello,

Is this the \nRF5_SDK_17.1.0_ddde560\examples\peripheral\spi example in nRF5 SDK?

Looking at the sdk_config.h file I can find that EasyDMA is enabled by SPI0_USE_EASY_DMA 1, so I don't see any reason why nrf_drv_spi_transfer() should have any delay between each byte.

Kenneth

[Triumph]

hello,

I delete the defination of SPIM and confirm that use the nrf_drv_spi_xfer() function.

//#define SPIM_PRESENT
//#define SPIM_COUNT 4

[Kenneth]

If you disable DMA, then the driver will write one byte at a time, so this is slower yes.

Kenneth

[Triumph]

Hi ~

Thank you for your patience, I read the driver's code and I know the driver write one byte at a time, but I can't understand the clock have so big gap between two bytes. Is the SPI's CLK right in my pasted picture? Can I make the SPI clock continuation?

Regards

Triumph

[Kenneth]

Hello,

Without EasyDMA then after each byte is transmitted, then the SPI interrupt needs to execute, and next byte needs to be written from the SPI interrupt. This will cause a few us delay between each byte. If you need the SPI clock continuation then you need to use SPI with EasyDMA (SPIM_PRESENT), then the entire SPI transfer will occur in one go without any delay between bytes.

Kenneth