Use SPI to interface to SDcard under Zephyr

RE: Use SPI to interface to SDcard under Zephyr

CktDesigner — Thu, 04 Mar 2021 16:08:59 GMT

Ok, thanks... I've been using Segger Embedded Studio...

Thanks for your assistance!

RE: Use SPI to interface to SDcard under Zephyr

Simon — Thu, 04 Mar 2021 09:01:31 GMT

[quote user="CktDesigner"]While it works, I still couldn't find the definition of DT_GPIO_LABEL_BY_IDX() which is in the define of DT_SPI_DEV_CS_GPIOS_LABEL() (in devicetree/spi.h) Yet it compiles!! So it must be somewhere![/quote]

DT_GPIO_LABEL_BY_IDX is defined at zephyr\include\devicetree\gpio.h. I would recommend you to download Visual Studio Code, which allows you to open the whole NCS and search for variables/functions/macros etc.. If you install Kconfig for the Zephyr Project and DeviceTree for the Zephyr Project you can use "Show Definition" to see where it's defined. As a sidenote, you could also open a Terminal in VS Code and do the actual development in the editor.

[quote user="CktDesigner"]I'm also confused when to use CONFIG statements vs defining things via device tree... [/quote]

Stuff that is defined in the device tree has to do with hardware and hardware configuration. E.g. SDA and SCL pins, what UART baud rate to use, pins for LEDs and buttons and so on. The CONFIG statements are used for configuring everything else, what drivers an libraries and drivers to use and to enable other firmware specific features.

Best regards,

Simon

RE: Use SPI to interface to SDcard under Zephyr

CktDesigner — Thu, 04 Mar 2021 03:16:19 GMT

Hi Simon,

Thanks! Adding CONFIG_GPIO=y to prj.conf solved it.

While it works, I still couldn't find the definition of DT_GPIO_LABEL_BY_IDX() which is in the define of DT_SPI_DEV_CS_GPIOS_LABEL() (in devicetree/spi.h) Yet it compiles!! So it must be somewhere!

I'm also confused when to use CONFIG statements vs defining things via device tree...

Thanks for your help!!!

RE: Use SPI to interface to SDcard under Zephyr

Simon — Wed, 03 Mar 2021 13:45:07 GMT

Try setting CONFIG_GPIO=y in the prj.conf file

The definition fo the macro DT_SPI_DEV_CS_GPIOS_LABEL is inside \zephyr\include\devicetree\spi.h

I think device_get_binding(DT_SPI_DEV_CS_GPIOS_LABEL(SPI_SDHC_NODE)) gets converted into device_get_binding("GPIO_1"). You could try to call this direcly to se if this "device" is actually correctly set up. In order for this to succeed, gpio1 needs to get added into the device tree (it seems like this is okay for you since you found it in zephyr.dts) and the driver needs to get set up as well (set CONFIG_GPIO=y), which will define an init function (DEVICE_DT_DEFINE-->gpio_nrfx_init()). If the init function is not called or fails, the device will be declared not ready and the call to device_get_binding will fail.

This is how I remembered how it worked, hopefully I got it correct :P

Best regards,

Simon