SPI Manager seems slower than using raw SPI master code

RE: SPI Manager seems slower than using raw SPI master code

Constantin — Fri, 13 Jul 2018 10:02:51 GMT

What should be ESB, enhanced shockburst?

RE: SPI Manager seems slower than using raw SPI master code

Håkon Alseth — Wed, 14 Feb 2018 15:33:26 GMT

Sounds like something in the system is blocking or delaying your transactions. It could be esb. You could try disabling that for testing purposes to double-check.

RE: SPI Manager seems slower than using raw SPI master code

Attila — Wed, 14 Feb 2018 14:00:08 GMT

Hi Håkon,

I'm only sending/receiving 2 bytes per transfer, hence the 16 x 2 byte array. (uint16_t rx_buffer[16])

At the time NRF_LOG was turned off, but I had the esb module on. Do you think that can cause slowdowns?

Thanks

RE: SPI Manager seems slower than using raw SPI master code

Håkon Alseth — Wed, 14 Feb 2018 13:54:55 GMT

Hi,

I did a 16 bytes x 16 transfers using the nrf_spi_mngr and it takes ~0.635 ms at 4 MHz at my end:

Not sure about the amount of bytes each queued transferred at your end, or what your speed is, but it is close to the theoretical transfer time of (1/4M * (16 bytes * 8) * 16 transfers) = 512 us.

Here's my test-code, based on example spi_master_using_nrf_spi_mngr in SDK 14.2.

devzone.nordicsemi.com/.../main.c

Could you check if disabling the NRF_LOG module improves the scenario at your end? Could be uart prints that slows you down.

Best regards,

Håkon