External SPI Flash Memory + File System + NRF 52832

[Prasad A]

Hi,

I am trying to implement a lightweight file system in my external flash memory (ISSI). After the implementation of file system, I want to store a .bin file and later access the file through c program. I am a beginner in nrf52 board and need some assistance in understanding the implementation method for the above.

1. I need some direction for implementing file system in nrf52832. I am using the following Software/Hardware tools:

• nRF52832
• NRF CONNECT SDK 2.5.1
• SPI FLash Memory: IS25LP128-JBLE
• vscode
• Windows 11 64 bits

       2. I would also like to if I can implement FATFS on the SPI flash memory using the nrf 52832. Is there a link for the lastest version of FAT FS code.

       3. I need some help in understanding if I can use supported files from nrf SDK v 2.5.1 for nrf52832 board? IS there some alteration needed before I upload them to my nrf 52832 board.

Best,

AP

[Shahin97]

Theses zephyr examples may be of some use to you - 

https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/subsys/fs

[Prasad A]

Will this work for nrf 52832 board?

As I have gone through the document and for external flash : "This type of configuration requires external flash device to be available on DK board. Currently following boards support the configuration: nrf52840dk_nrf52840 by nrf52840dk_nrf52840_qspi configuration." . SInce I have a nrf 52832dk board it does not support this board right?

[Shahin97]

QSPI could be corrected using the overlay file.

Unsure of the meaning of this statement, but QSPI will not work on the nrf52832, only regular SPI

[Prasad A]

Got it!.

the other statement was: After the implemetation of FS in exteranl flash. Later Can I store a file (a binary file ".bin") in this external flash and be able to read/write files using spi driver.

[Shahin97]

The littlefs example creates, reads and writes a file called pattern.bin, You'd have to analyse how the FATFS example works, should you wish to use that instead

[dejans]

Hi Prasad A ,

Regarding file systems, you could have a look at file_systems and samples.

Please let me know if you have any further questions.

Best regards,
Dejan

[Prasad A]

Hey dejans,

I was looking in the Links you provided, the ideal file to flash to an external spi flash memory seems to be :

samples/subsys/usb/mass/ : since its is an example of USB Mass Storage device that uses FAT FS driver with RAM or *SPI connected FLASH*, or LittleFS in flash, depending on the sample configuration.

But due to the defintion of USB I am currently using the "samples/subsys/fs/littlefs" and try to change the std, overlay and prj.conf. Therefore I need some help there.

I have a external SPI NOR FLASH (25lp128 from ISSI) connected to my nrf52dk_52832 development board kit.

The connection are:

• SPI_CE_PIN = P0.22 // chip enable
• SPI_MISO_PIN = P0.23 // SO
• SPI_MOSI_PIN = P0.24 // SI
• SPI_SCK_PIN = P0.25 //SCK
• SPI_HOLD_PIN = P0.11 //HOLD or RESET (not sure if it should be connected)
• SPI_WP_PIN = P0.12 // Write protect (not sure if it should be connected)

My nrf52dk_52832.dts is:

/dts-v1/;
#include <nordic/nrf52832_qfaa.dtsi>
#include "nrf52dk_nrf52832-pinctrl.dtsi"
#include <zephyr/dt-bindings/input/input-event-codes.h>

/ {
	model = "Nordic nRF52 DK NRF52832";
	compatible = "nordic,nrf52-dk-nrf52832";

	chosen {
		zephyr,console = &uart0;
		zephyr,shell-uart = &uart0;
		zephyr,uart-mcumgr = &uart0;
		zephyr,bt-mon-uart = &uart0;
		zephyr,bt-c2h-uart = &uart0;
		zephyr,sram = &sram0;
		zephyr,flash = &flash0;
		zephyr,code-partition = &slot0_partition;
	};

	pwmleds {
		compatible = "pwm-leds";
		pwm_led0: pwm_led_0 {
			pwms = <&pwm0 0 PWM_MSEC(20) PWM_POLARITY_INVERTED>;
		};
	};

	arduino_header: connector {
		compatible = "arduino-header-r3";
		#gpio-cells = <2>;
		gpio-map-mask = <0xffffffff 0xffffffc0>;
		gpio-map-pass-thru = <0 0x3f>;
		gpio-map = <0 0 &gpio0 3 0>,	/* A0 */
			   <1 0 &gpio0 4 0>,	/* A1 */
			   <2 0 &gpio0 28 0>,	/* A2 */
			   <3 0 &gpio0 29 0>,	/* A3 */
			   <4 0 &gpio0 30 0>,	/* A4 */
			   <5 0 &gpio0 31 0>,	/* A5 */
			   <6 0 &gpio0 11 0>,	/* D0 */
			   <7 0 &gpio0 12 0>,	/* D1 */
			   <8 0 &gpio0 13 0>,	/* D2 */
			   <9 0 &gpio0 14 0>,	/* D3 */
			   <10 0 &gpio0 15 0>,	/* D4 */
			   <11 0 &gpio0 16 0>,	/* D5 */
			   <12 0 &gpio0 17 0>,	/* D6 */
			   <13 0 &gpio0 18 0>,	/* D7 */
			   <14 0 &gpio0 19 0>,	/* D8 */
			   <15 0 &gpio0 20 0>,	/* D9 */
			   <16 0 &gpio0 22 0>,	/* D10 */
			   <17 0 &gpio0 23 0>,	/* D11 */
			   <18 0 &gpio0 24 0>,	/* D12 */
			   <19 0 &gpio0 25 0>,	/* D13 */
			   <20 0 &gpio0 26 0>,	/* D14 */
			   <21 0 &gpio0 27 0>;	/* D15 */
	};

	arduino_adc: analog-connector {
		compatible = "arduino,uno-adc";
		#io-channel-cells = <1>;
		io-channel-map = <0 &adc 1>,	/* A0 = P0.3 = AIN1 */
				 <1 &adc 2>,	/* A1 = P0.4 = AIN2 */
				 <2 &adc 4>,	/* A2 = P0.28 = AIN4 */
				 <3 &adc 5>,	/* A3 = P0.29 = AIN5 */
				 <4 &adc 6>,	/* A4 = P0.30 = AIN6 */
				 <5 &adc 7>;	/* A5 = P0.31 = AIN7 */
	};

	/* These aliases are provided for compatibility with samples */
	aliases {

	};
};

&adc {
	status = "okay";
};

&uicr {
	gpio-as-nreset;
};

&gpiote {
	status = "okay";
};

&gpio0 {
	status = "okay";
};

arduino_serial: &uart0 {
	status = "okay";
	compatible = "nordic,nrf-uarte";
	current-speed = <115200>;
	pinctrl-0 = <&uart0_default>;
	pinctrl-1 = <&uart0_sleep>;
	pinctrl-names = "default", "sleep";
};

arduino_i2c: &i2c0 {
	compatible = "nordic,nrf-twi";
	status = "okay";
	pinctrl-0 = <&i2c0_default>;
	pinctrl-1 = <&i2c0_sleep>;
	pinctrl-names = "default", "sleep";
};


&spi0 {
	compatible = "nordic,nrf-spi";
	/* Cannot be used together with i2c0. */
	/* status = "okay"; */
	pinctrl-0 = <&spi0_default>;
	pinctrl-1 = <&spi0_sleep>;
	pinctrl-names = "default", "sleep";
};

&spi1 {
	compatible = "nordic,nrf-spi";
	status = "okay";
	pinctrl-0 = <&spi1_default>;
	pinctrl-1 = <&spi1_sleep>;
	pinctrl-names = "default", "sleep";
};

arduino_spi: &spi2 {
	compatible = "nordic,nrf-spi";
	status = "okay";
	cs-gpios = <&arduino_header 16 GPIO_ACTIVE_LOW>; /* D10 */
	pinctrl-0 = <&spi2_default>;
	pinctrl-1 = <&spi2_sleep>;
	pinctrl-names = "default", "sleep";
};

&flash0 {

	partitions {
		compatible = "fixed-partitions";
		#address-cells = <1>;
		#size-cells = <1>;

		boot_partition: partition@0 {
			label = "mcuboot";
			reg = <0x00000000 0xc000>;
		};
		slot0_partition: partition@c000 {
			label = "image-0";
			reg = <0x0000C000 0x37000>;
		};
		slot1_partition: partition@43000 {
			label = "image-1";
			reg = <0x00043000 0x37000>;
		};
		storage_partition: partition@7a000 {
			label = "storage";
			reg = <0x0007a000 0x00006000>;
		};
	};
};

During build there is error showing : unknwon node type "nordic,nrf52-dk-nrf52832"

My nrf52dk_52832.overlay is:

/ {
aliases {
    spi-flash0 = &flash_25lp128;
	};
    chosen 
	{ nordic,pm-ext-flash = &flash_25lp128; }; 
};

&spi2 {
	compatible = "nordic,nrf-spi"; //nordic,nrf-spi
	status = "okay";
	cs-gpios = <&gpio0 16 GPIO_ACTIVE_LOW>; /* P0.22 */
	pinctrl-0 = <&spi2_default>;
	pinctrl-1 = <&spi2_sleep>;
	pinctrl-names = "default", "sleep";

	flash_25lp128: flash_25lp128@0 {
		compatible = "jedec,spi-nor";
		reg = <0>;
		label = "FLASH_25LP128";
		// power_resources = <&flash_on>;
		spi-max-frequency = <8000000>;
		size = <134217728>;
		wp-gpios = <&gpio0 11 GPIO_ACTIVE_LOW>; // gpio 0 pin P0.11
		hold-gpios = <&gpio0 12 GPIO_ACTIVE_LOW>; // gpio 0 pin P0.12
		jedec-id = [9d 60 18];
	};
};

/*
sck-pin = <25>; // gpio 0 pin P0.25
mosi-pin = <23>; // gpio 0 pin P0.23
miso-pin = <24>; // gpio 0 pin P0.24 */

My prj.conf is : (same as from the samples/subsys/fs/littlefs/)

# Optionally force the file system to be recreated
#CONFIG_APP_WIPE_STORAGE=y

# fs_dirent structures are big.
CONFIG_MAIN_STACK_SIZE=4096

# Let __ASSERT do its job
CONFIG_DEBUG=y

CONFIG_LOG=y
CONFIG_LOG_MODE_MINIMAL=y

CONFIG_FLASH=y
CONFIG_FLASH_MAP=y
CONFIG_FLASH_PAGE_LAYOUT=y

CONFIG_FILE_SYSTEM=y
CONFIG_FILE_SYSTEM_LITTLEFS=y

There is a warning for this file:

CONFIG_FLASH_MAP was assigned the value y, but got the value n. Missing dependencies:
FLASH_HAS_DRIVER_ENABLED

CONFIG_FLASH_PAGE_LAYOUT was assigned the value y, but got the value n. Missing dependencies:
FLASH_HAS_PAGE_LAYOUT

CONFIG_SPI_NOR was assigned the value y, but got the value n. Missing dependencies:
DT_HAS_JEDEC_SPI_NOR_ENABLED

CONFIG_SPI_NOR_FLASH_LAYOUT_PAGE_SIZE couldn't be set. Missing dependencies:
SPI_NOR

As I am new to nrf52dk boards, few basic questions:

1. In my .dts file, should I delete all gpio assignments other than those menioned in spi2?
2. How should I change my config (prj.config) file?
3. For the above configuration I am using the code given in:  

   "samples/subsys/fs/littlefs"

   instead of :

   "samples/subsys/usb/mass/" ? or "samples/subsys/fs/fs_sample"

4. The prj.config file shows many error on "CONFIG_SPI_NOR" and others, how do I correct it for my external spi nor flash from nrf52dk_52832 development kit?
   
   

Best,

AP