Getting started with spi and i2c on nrf connect sdk

RE: Getting started with spi and i2c on nrf connect sdk

Albrecht Markus Schellenberger — Wed, 21 Apr 2021 15:23:01 GMT

In general, I recommend you switching over to the NCS since we are not adding any new features to the SDK anymore.

You can check out this link for available examples and documentation.

Regarding the time for porting your code: It is of course hard to give you exact numbers, but I do not expect it to take too much time. The API’s are quite similar in general.

A good way to start would be letting the NCS compiler run through the ported code.

Cheers,

Markus

RE: Getting started with spi and i2c on nrf connect sdk

madblue — Wed, 21 Apr 2021 10:12:09 GMT

Thanks Markus,

it was helpful, i am able read/write data using the zephyr apis.

I am still a bit confused about the spi data structures for read/write and also the 'patch_spi_read' api.

It doesn't seem to work but i can figure that out.

I will try out the i2c in the same way.

I have a general question regarding the nrfconnect sdk and zephyr,

As I have mentioned in the initial question, i am trying to port my application code to nrf connect sdk from nrf5 sdk14.00. i am a bit worried about the time required to completely port the code.

My application requirements are,

dfu bootloader, 2 spi, a flash file system(little fs), extended BLE mtu size(>150), low BLE connection interval (<50 ms), 2 timers, 1 i2c and a watchdog.

Is the nrfconnect sdk drivers required for my application is mature enough? Is there enough examples/documentation available to make the process as quick as possible ?

Just to make sure it is the right time to port the code to nrfconnect sdk.

I am adding my code here.

Hope this would be helpful for someone.

/*
 * Copyright (c) 2012-2014 Wind River Systems, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr.h>
#include <sys/printk.h>
#include <zephyr/types.h>
#include <stddef.h>
#include <string.h>
#include <errno.h>
#include <drivers/spi.h>
#include <drivers/gpio.h>


#if !DT_NODE_EXISTS(DT_NODELABEL(spi1))
#error "0oops"
#endif
#define SPI1 DT_NODELABEL(spi1)

int spi_cs_pin = 15;
int led_pin = 14;

static struct spi_config spi_cfg = {
	.operation = SPI_WORD_SET(8) | SPI_TRANSFER_MSB,
	.frequency = 4000000,
	.slave = 0,
};
struct device * spi_dev = NULL;
struct device * gpio0_dev = NULL;
struct device * gpio1_dev = NULL;

bool patch_spi_read(uint8_t * tx_ptr, uint8_t * rx_ptr, uint8_t tx_len, uint8_t rx_len){

	int err;

	struct spi_buf tx_buf[2];
	struct spi_buf rx_buf[2];
	struct spi_buf_set tx;
	struct spi_buf_set rx;

	tx_buf[0].buf = tx_ptr;
	tx_buf[0].len = 1;

	rx_buf[0].buf = rx_ptr;
	rx_buf[0].len = 1;

	rx_buf[1].buf = &rx_ptr[1];
	rx_buf[1].len = 4;

	tx.buffers = tx_buf;
	tx.count = 1;
	rx.buffers = rx_buf;
	rx.count = 2;

	gpio_pin_set(gpio0_dev, spi_cs_pin, 0);
	//err = spi_transceive(spi_dev, &spi_cfg, &tx, &rx);k_sleep(K_MSEC(30));
	err = spi_write(spi_dev, &spi_cfg, &tx);

	if (err) {
		printk("spi write error: %d\n", err);
		return false;
	}
	k_sleep(K_MSEC(3));
	err = spi_read(spi_dev, &spi_cfg, &rx);
	if (err) {
		printk("spi read error: %d\n", err);
		return false;
	}else {
		printk("tx data %x\n", tx_ptr[0]);

		for (size_t i = 0; i < 4; i++) {
			printk("RX recv: %d \n", rx_ptr[i]);
		}
	}
	//gpio_pin_set(gpio0_dev, spi_cs_pin, 1);
	return true;
}

void main(void)
{
	printk("Hello World! %s\n", CONFIG_BOARD);

	gpio0_dev= device_get_binding("GPIO_0");

	gpio_pin_configure(gpio0_dev, spi_cs_pin, GPIO_OUTPUT); //p0.03 == led_pin2
	gpio_pin_configure(gpio0_dev, led_pin, GPIO_OUTPUT); //p0.03 == LED2
	gpio_pin_set(gpio0_dev, spi_cs_pin, 0);


	printk(" SPI init\n");
	spi_dev = device_get_binding(DT_LABEL(SPI1));
	if (spi_dev == NULL) {
		printk("Could not find SPI driver\n");
		return;
	}else printk("spi init success\n");

	k_sleep(K_MSEC(50));

	static uint8_t tx_buffer[16] = {0x1f, 00, 00, 00};
	static uint8_t rx_buffer[16];
	patch_spi_read(tx_buffer, rx_buffer, 1, 4);

	while(true){
		gpio_pin_set(gpio0_dev, led_pin, 0xff);
		k_sleep(K_MSEC(2000));

		gpio_pin_set(gpio0_dev, led_pin, 0);
		k_sleep(K_MSEC(30));
	}

}

RE: Getting started with spi and i2c on nrf connect sdk

Albrecht Markus Schellenberger — Tue, 20 Apr 2021 13:42:06 GMT

Chapter 3.4 of Simons tutorial gives you a basic introduction on how to create an overlay file. I hope this will be useful for you.

Cheers!

Markus

RE: Getting started with spi and i2c on nrf connect sdk

madblue — Tue, 20 Apr 2021 12:49:10 GMT

I am using a custom board based on nrf52840.

I have not created a new board but edited the existing .dts file according my custom board specifications.

I have ran it on a dk also but getting the same error.

i have chosen a ble code as my base, let me get back to you after trying it out with simple example.

This how the zephyr.dts file looks like,

		};
		spi0: spi@40003000 {
			#address-cells = < 0x1 >;
			#size-cells = < 0x0 >;
			reg = < 0x40003000 0x1000 >;
			interrupts = < 0x3 0x1 >;
			status = "disabled";
			label = "SPI_0";
			compatible = "nordic,nrf-spi";
			sck-pin = < 0x1f >;
			mosi-pin = < 0x1e >;
			miso-pin = < 0x28 >;
		};
		spi1: spi@40004000 {
			#address-cells = < 0x1 >;
			#size-cells = < 0x0 >;
			reg = < 0x40004000 0x1000 >;
			interrupts = < 0x4 0x1 >;
			status = "okay";
			label = "SPI_1";
			compatible = "nordic,nrf-spi";
			sck-pin = < 0xd >;
			mosi-pin = < 0xe >;
			miso-pin = < 0x10 >;
		};
		spi2: spi@40023000 {
			#address-cells = < 0x1 >;
			#size-cells = < 0x0 >;
			reg = < 0x40023000 0x1000 >;
			interrupts = < 0x23 0x1 >;
			status = "disabled";
			label = "SPI_2";
			compatible = "nordic,nrf-spi";
			sck-pin = < 0x13 >;
			mosi-pin = < 0x14 >;
			miso-pin = < 0x15 >;
		};

How do i create an overlay file ?

RE: Getting started with spi and i2c on nrf connect sdk

Albrecht Markus Schellenberger — Tue, 20 Apr 2021 12:28:58 GMT

There are no silly questions, only silly answers. Right? ;-)

Are you using your own board together with the nRF52840 or a DK? I am asking because if you work with the nRF52840 DK for instance, you do not need an overlay file to get SPI1 to work. It is already part of the device tree, which you can check via a file called zephyr.dts located in: ../<your build folder>/zephyr/.

spi1: spi@40004000 {
	#address-cells = < 0x1 >;
	#size-cells = < 0x0 >;
	reg = < 0x40004000 0x1000 >;
	interrupts = < 0x4 0x1 >;
	status = "okay";
	label = "SPI_1";
	compatible = "nordic,nrf-spi";
	sck-pin = < 0x1f >;
	mosi-pin = < 0x1e >;
	miso-pin = < 0x28 >;
};

I ran your C-snippet through a simple “Hello World” application on the nRF52840 DK and the binding worked fine.

Regards,

Markus

RE: Getting started with spi and i2c on nrf connect sdk

madblue — Mon, 19 Apr 2021 15:54:59 GMT

Hi,

That is pretty good, thanks.

I have tried a simple test code for spi but i am not able to get the device_get_binding().

prj.config

CONFIG_NCS_SAMPLES_DEFAULTS=y

CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME="Nordic_Blinky"

# Enable the LBS service
CONFIG_BT_LBS=y
CONFIG_BT_LBS_POLL_BUTTON=y
CONFIG_DK_LIBRARY=y

CONFIG_GPIO=y
CONFIG_SPI=y
CONFIG_I2C=n
CONFIG_NRFX_SPIM=n
CONFIG_NRFX_SPIM1=n


CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048

#if !DT_NODE_EXISTS(DT_NODELABEL(spi1))
#error "whoops"
#endif
#define SPI1 DT_NODELABEL(spi1)

    struct device * spi_dev;
    spi_dev = device_get_binding(DT_LABEL(SPI1));   


	const char* const spiName = "SPI_1";
	//spi_dev = device_get_binding(spiName);
    spi_dev = device_get_binding(MYSPI);
	if (spi_dev == NULL) {
		printk("Could not find SPI driver\n");
		return;
	}else printk("spi success");
	
	
	uint8_t tx_buf[4]={(0x0F<<1 ) | 0x01};
	uint8_t rx_buf[4]={0};
	struct spi_buf spi_tx_buf_struct;
	spi_tx_buf_struct.buf = tx_buf;
	spi_tx_buf_struct.len = 4;

	struct spi_buf spi_rx_buf_struct;
	spi_tx_buf_struct.buf = rx_buf;
	spi_tx_buf_struct.len = 4;

	struct spi_buf_set spi_bufs;
	spi_bufs.buffers = &spi_tx_buf_struct;
	spi_bufs.count = 4;
	struct spi_buf_set spi_bufs_rx;
	spi_bufs.buffers = &spi_rx_buf_struct;
	spi_bufs.count = 4;
	//


	spi_transceive(spi_dev, &spi_cfg, &spi_bufs, &spi_bufs_rx);
	//spi_write(spi_dev, &spi_cfg, &spi_bufs);
	k_sleep(K_MSEC(100));
	printk("read %d %d %d \n\n", rx_buf[1], rx_buf[2], rx_buf[3]);

I have also had a look at the "device tree how to ",


my .dts for 52840,

&spi1 {
	compatible = "nordic,nrf-spi";
	/* Cannot be used together with i2c0. */
	/* status = "okay"; */
	sck-pin = <13>;
	mosi-pin = <14>;
	miso-pin = <16>;
};

zephyr.dts, 

spi1: spi@40004000 {
	#address-cells = < 0x1 >;
	#size-cells = < 0x0 >;
	reg = < 0x40004000 0x1000 >;
	interrupts = < 0x4 0x1 >;
	status = "disabled";
	label = "SPI_1";
	compatible = "nordic,nrf-spi";
	sck-pin = < 0xd >;
	mosi-pin = < 0xe >;
	miso-pin = < 0x10 >;
};

I think It initializes the spi, my i am getting this error,

*** Booting Zephyr OS build v2.4.99-ncs1  ***␍␊
Starting Bluetooth Peripheral LBS example␍␊
 SPI init␍␊
spi successI: CS control inhibited (no GPIO device)␍␊
E: ***** BUS FAULT *****␍␊
E:   Precise data bus error␍␊
E:   BFAR Address: 0x20040000␍␊
E: r0/a1:  0x40004000  r1/a2:  0x20002e1c  r2/a3:  0x0003dbb8␍␊
E: r3/a4:  0x20002448 r12/ip:  0x20002e28 r14/lr:  0x0001da9b␍␊
E:  xpsr:  0x21000014␍␊
E: Faulting instruction address (r15/pc): 0x00024216␍␊
E: >>> ZEPHYR FATAL ERROR 0: CPU exception on CPU 0␍␊
E: Fault during interrupt handling␍␊

I have tied the cs pin low always.

Do i have to specify the pin numbers elsewhere other than the .dts file ? does it get override from somewhere else ?

RE: Getting started with spi and i2c on nrf connect sdk

Albrecht Markus Schellenberger — Mon, 19 Apr 2021 14:17:20 GMT

Hello,

I can recommend a tutorial written by my colleague Simon. Chapter 1.2 should be of special interest for you:

https://devzone.nordicsemi.com/nordic/nrf-connect-sdk-guides/b/getting-started/posts/nrf-connect-sdk-tutorial---part-3-ncs-v1-4-0#h79sk0f70607qwcyitkx2xn61bmh9mo

Note that the tutorial is not up to date anymore, so instead of using

CONFIG_I2C_1=y

in prj.conf, you have to use this option instead:

CONFIG_I2C=y

I hope this will help you! Let me know if you have any more questions.

Regards,

Markus