SDHC SPI Send Command

[dario.sortino]

Hello.

I have a custom board featuring nRF5340. I placed a microSD card reader in my board connected to SPI. I followed the fatfs zephyr example, but I'm struggling in mounting the disk.

I can correctly see the block count, sector size and capacity of the microSD, but as soon as I try to run fs_mount(&mp), the board resets.

When debugging, I saw that the board resets as it tries to run the function sdhc_spi_send_cmd

I don't know where the problem can be, since as I said I can correctly see the capacity of the card (I'm using a Premium microSDHC 32gb card by Verbatim )

I already tried to format the card both with Windows10 and the program SDCardFormatter, but nothing changed.

My devicetree for the spi/sd device is 

&spi1 {
	compatible = "nordic,nrf-spim";
	status = "okay";
	cs-gpios = < &gpio0 7 GPIO_ACTIVE_LOW >;
	sck-pin = < 8 >;
	mosi-pin = < 9 >;
	miso-pin = < 10 >;
	sdhc0: sdhc@0 {
		compatible = "zephyr,sdhc-spi-slot";
		reg = <0>;
		status = "okay";
		label = "SDHC0";
		mmc {
			compatible = "zephyr,sdmmc-disk";
			status = "okay";
		};
		spi-max-frequency = <16000000>;
	};	
};

And my connector is the following

[Simonr]

Hi

I see that you've set the SPI max frequency to 16MHz, but the SPI1 instance in the nRF5340 does not support higher data rates than 8Mbps, so can you try lowering the spi-max-frequency down to 8000000?

What SDK version are you using for development? When debugging, do you see any kinds of error codes as when the application moves into fs_mount(), or where does the debugging session end up?

Best regards,
Simon

[dario.sortino]

Hi Simonr.

I tried to lower the SPI freq to 8M, and this time I cannot even see the size of the SD. If you take into consideration the fat_fs example, with 8M I enter this control

if (disk_access_init(disk_pdrv) != 0) {

            printk("Storage init ERROR!\n");

            break;

        }

While with 16M I successfully skip that and while debugging it ends up to the first sdhc_spi_send_cmd that it encounters deep down to the function fs_mount inside functions, showing no errors but rebooting the MCU.

My SDK is NCS 2.2.0.

[Simonr]

Hi

Hmm, that's very strange, a few more things you can try:

• Have you tested this on a Development kit yet. That way we can narrow this down to whether it's a HW or SW issue at least.
• You can also try to set the frequency even lower (1MHz for example) to see if you still see the storage init ERROR with that frequency setting as well.
• Another thing I noticed is that you're using a deprecated way of setting your pins on. Please try using the pin control to set the SPI pins. You can see how it can be done in this SPI example by my colleague Torbjørn.
• If possible, it could also be helpful to get a scope trace of the SPI pins to see that the expected data is output on them, and what exactly happens before and as the device resets.

Best regards,

Simon

[dario.sortino]

I updated the overlay as it follows:

&spi1 {
	compatible = "nordic,nrf-spim";
	status = "okay";
	cs-gpios = < &gpio0 7 GPIO_ACTIVE_LOW >;
	pinctrl-0 = <&spi1_default>;
	pinctrl-names = "default";
	sdhc0: sdhc@0 {
		compatible = "zephyr,sdhc-spi-slot";
		reg = <0>;
		status = "okay";
		label = "SDHC0";
		mmc {
			compatible = "zephyr,sdmmc-disk";
			status = "okay";
		};
		spi-max-frequency = <16000000>;		
	};	
};

Using pinctrl as:

spi1_default: spi1_default{
	group1 {
		psels = <NRF_PSEL(SPIM_SCK, 0, 8)>,
			<NRF_PSEL(SPIM_MISO, 0, 10)>,
			<NRF_PSEL(SPIM_MOSI, 0, 9)>;
	};

};

With this setting (16MHz), I now encounter the storage init error, so there is something odd.

I do not have a uSD slot that I can plug into the devkit, so It would be prone to errors to unsolder my socket and hand soldering all the connections to the dk pins.

Should I init in some way the SPI in my code? Even tough in the example there is not any kind of initialization

[Simonr]

dario.sortino said:

I now encounter the storage init error

What error exactly is this? What function returns the error, and what error code do you see? Did you try to set the frequency even lower (1MHz for example) to see if you still see the storage init ERROR with that frequency setting as well. If possible, can you get a scope trace of the SPI pins to see that the expected data is output on them, and what exactly happens before and as the device resets.

Best regards,

Simon