NRF9160 SD card access via SPI

[Zack Mak]

Hi,

I am following a client case that they have issue on accessing SD card via SPI port.

I used the sample project fat_fs on nrf9160_pca10090 DK and used SPI_3 to access the SD card.

After some testing and I face the exact same issue from other thread.

https://devzone.nordicsemi.com/f/nordic-q-a/58558/reading-sd-card-on-nrf9160dk

(I opened this new case as suggested by Nordic FAE)

I ran debug mode and found that the CS pin wasn't registered in the device context. Here is some of my findings. (tested on SDK v1.2.0)

1. Set breakpoint at line 220 of spi_nrfx_spim.c. The dev_data->ctx->config->cs was NULL, causing "CS control inhibited (no GPIO device)" (line 177, spi_context.h)
2. For the structure spi_3z_config.
   1. the spi_3z_config.config.ss_pin = 0xff. In this structure the ss_pin was set as unused. (line 409, spi_nrfx_spim.c)
   2. I changed the ss_pin value to "DT_NORDIC_NRF_SPIM_SPI_##idx##_CS_GPIOS_PIN", now the spi_3z_config.config.ss_pin = 16 (CS pin was set 16 in the DTS overlay)
   3. But this change did not help to update the dev_data->ctx->config->cs. The value was still NULL.

I believe there is something missing during the initialization of the SPI device in the OS.

Any help is appreciated.

Thanks

[Øyvind]

Hello, 

I added the CONFIG_GPIO=y to prj.conf and that removed the "CS control inhibited (no GPIO device)" error on my side.

Have forwarded this to our NCS team, and will get back to you/customer ASAP.

Kind regards, 
Øyvind

[Zack Mak]

Hi,

FYR

I added the CONFIG_GPIO=y to prj.conf and the error message is still there.

I also tried the hex file that you uploaded in another thread. The error message is still there.

Thanks

[Øyvind]

Hello, 

I gave an answer to the customer.

Kind regards,
Øyvind

[Zack Mak]

Hi,

I fixed that problem and now able to access SD cards.

The "no GPIO device" message turns out unrelated to this issue at all. The CS pin is actually controlled by the SDHC_SPI driver, not the SPI driver.

The solution to this problem is to set the "Size of RAM buffers for SPIM peripherals" to some number. If the size is set to 0, the SPI transceive function will always return error.

Best regards,

[Øyvind]

Hi Zack, 

Zack Mak said:

The solution to this problem is to set the "Size of RAM buffers for SPIM peripherals" to some number. If the size is set to 0, the SPI transceive function will always return error.

Thank you for pointing that out. I was not aware of this as I have not been able to test with an SD card. 

The customer writes that he still has issues, an error from disk_access_init(). Are you getting this as well?

-Øyvind

 

[Zack Mak]

I didn't get any error in fat_fs demo once the SPI buffer is assigned. I could mount the card and read the root folder structure.