Sending single bytes over hw SPI; 0xFF appended every other time

RE: Sending single bytes over hw SPI; 0xFF appended every other time

feistyz — Tue, 21 Aug 2018 23:05:47 GMT

Turning off easy DMA seems to fix this issues as well. Of course, that's far from great as it disables DMA.

//In sdk_config.h
#ifndef SPI0_USE_EASY_DMA
#define SPI0_USE_EASY_DMA 0
#endif

RE: Sending single bytes over hw SPI; 0xFF appended every other time

leonhart88 — Sun, 15 Apr 2018 17:22:05 GMT

You can also achieve single byte transfers by doing something like the following:

nrf_drv_spi_transfer(&m_spi_master_0, spiTransmitBuffer, 1, NULL, 0);

This has worked for me when needing to do a single byte command for peripherals in order to set registers.

RE: Sending single bytes over hw SPI; 0xFF appended every other time

Ed — Tue, 14 Nov 2017 01:08:59 GMT

This is a very big flaw in the product

RE: Sending single bytes over hw SPI; 0xFF appended every other time

bjorn-spockeli — Thu, 15 Sep 2016 06:47:39 GMT

It will probably be low priority since there is a software workaround for this issue.

RE: Sending single bytes over hw SPI; 0xFF appended every other time

nordictester — Wed, 14 Sep 2016 17:12:12 GMT

Evidently this is an issue with all nRF52832 ICs released as of September, 2016, including Engineering revs A, B, and C, and Rev 1. This includes ICs marked QFAA-B00, CHAA-B00, CIAA-B00, QFAA-BB0, CHAA-BA0, CIAA-BA0, QFAA-BA0, CHAA-AA0, QFAA-AA0, QFAA-AC0, CGAA-AA0. Hope this helps someone

RE: Sending single bytes over hw SPI; 0xFF appended every other time

nordictester — Wed, 14 Sep 2016 17:07:16 GMT

thanks for the quick response

RE: Sending single bytes over hw SPI; 0xFF appended every other time

nordictester — Wed, 14 Sep 2016 17:07:11 GMT

Thanks, is this going to be fixed in the next chip revision? Seems like a pretty big flaw. Would probably be helpful to make note of this in the nRF52 sdk documentation, on the spi master driver page.

RE: Sending single bytes over hw SPI; 0xFF appended every other time

bjorn-spockeli — Wed, 14 Sep 2016 11:17:06 GMT

Hi Nordictester,

as @rols (RK) explains, this is a known issue with the nRF52, [58] SPIM: An additional byte is clocked out when RXD.MAXCNT = 1, which is described here in the errata.

I have added the workaround desecribed in the errata to the peripheral SPI example from the SDK( /examples/peripheral/spi), the modified example is attached. Please note that the workaround is implemented using the PPI and GPIOTE drivers and not writting directly to the peripheral registers.

Attachment:

spi_pan58_workaround_sdk12.zip

Note: The zip must be extracted to SDK-folder/examples/peripheral, otherwise the include paths will be incorrect.

RE: Sending single bytes over hw SPI; 0xFF appended every other time

RK — Wed, 14 Sep 2016 00:02:56 GMT

All documented in the errata section

infocenter.nordicsemi.com/index.jsp