Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

jjifa — Wed, 01 Sep 2021 17:35:15 GMT

I faced the same problem.
there is a difference, only 0x00 is entered in MISO.
Have you solved this problem?

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

yanchevm — Tue, 03 Dec 2019 20:57:57 GMT

Hi RenatoMorelli,

I'm also trying to create project with nrf52 + LIS3DH. Can you please attach or send me the example project ?

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

RenatoMorelli — Wed, 02 May 2018 23:53:45 GMT

Hey, Agam, try these changes on your code:

static uint8_t       m_tx_buf[] = {0x8F,0x00};

void spi_event_handler(nrf_drv_spi_evt_t const * p_event,
                       void *                    p_context)
{
    spi_xfer_done = true;
    NRF_LOG_INFO("Transfer completed.");
    if (m_rx_buf[1] != 0) // change the byte to compare here
    {
        NRF_LOG_INFO(" Received:");
        NRF_LOG_INFO(" %X",m_rx_buf[1]); // here to print it
//        NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));
    }
}

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

RenatoMorelli — Wed, 02 May 2018 23:44:59 GMT

Yep, you got it right. I was mistakenly sending, for the scopeshots, 0x87 instead of 0x8F (I even tried to delete the comment, but I couldn't)

Now I got it working but had to reduce the speed (as you pointed above) and to modify the loop back example to check for the second byte in the answer.

Really had to use the scope for this (8MHz was inserting harmonics in my clock signal and the reverse analysis from an old code got me to try the mode 3, the one that worked).

TL;DR I used mode 0 and 3 to make it work

Here I share my happiness with you, thansk so much hmolesworth

MOSI

MISO

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

hmolesworth — Wed, 02 May 2018 23:21:06 GMT

Isn't that the answer? The 'scope shows you are sensing 0x87 which agrees with the code above; Whoami requires 0x8F ..

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

RenatoMorelli — Wed, 02 May 2018 23:14:19 GMT

It is weird, but I used the example from the sdk 14.2. I just modified the buffer to the register I wanted.

#include "nrf_drv_spi.h"
#include "app_util_platform.h"
#include "nrf_gpio.h"
#include "nrf_delay.h"
#include "boards.h"
#include "app_error.h"
#include <string.h>
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#include "nrf_gpio.h"

#define SPI_INSTANCE  0 /**< SPI instance index. */
static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */
static volatile bool spi_xfer_done;  /**< Flag used to indicate that SPI instance completed the transfer. */

//sck//scl 03
//miso//sdo 28
//mosi//sda 4
//ss/cs 29 

//#define TEST_STRING "Nordic"
static uint8_t       m_tx_buf[] = {0x87,0x00};           /**< TX buffer. */
static uint8_t       m_rx_buf[] = {0x00,0x00};    /**< RX buffer. */
static const uint8_t m_length = sizeof(m_tx_buf);        /**< Transfer length. */

/**
 * @brief SPI user event handler.
 * @param event
 */
void spi_event_handler(nrf_drv_spi_evt_t const * p_event,
                       void *                    p_context)
{
    spi_xfer_done = true;
    NRF_LOG_INFO("Transfer completed.");
    if (m_rx_buf[0] != 0)
    {
        NRF_LOG_INFO(" Received:");
        NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));
    }
}

int main(void)
  {
    bsp_board_leds_init();

    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();
    
    NRF_LOG_INFO("SPI example.");

    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
    spi_config.ss_pin    = SPI_SS_PIN;
    spi_config.miso_pin  = SPI_MISO_PIN;
    spi_config.mosi_pin  = SPI_MOSI_PIN;
    spi_config.sck_pin   = SPI_SCK_PIN;
    spi_config.frequency = NRF_SPI_FREQ_125K;
    spi_config.bit_order = NRF_DRV_SPI_BIT_ORDER_MSB_FIRST;
    spi_config.mode      = NRF_DRV_SPI_MODE_3;           
    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));

    while (1)
    {
        // Reset rx buffer and transfer done flag
        memset(m_rx_buf, 0, m_length);
        spi_xfer_done = false;

        bsp_board_led_invert(BSP_BOARD_LED_0);
        
        APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));

        while (!spi_xfer_done)
        {
            __WFE();
        }

        NRF_LOG_FLUSH();

        bsp_board_led_invert(BSP_BOARD_LED_0);
        nrf_delay_ms(1000);
    }
}

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

hmolesworth — Wed, 02 May 2018 22:51:15 GMT

The LIS3DH clocks data in on the rising clock edge; hence last 'scope screenshot shows a transmitted command value of 0x87 not 0x8F. The traces would be easier to read if they were vertically separated slightly .. while still overlapping. Perhaps post the function you are using to generate this trace, in case we see something there ..

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

RenatoMorelli — Wed, 02 May 2018 19:17:10 GMT

I tried this, not working :/

I appealed to the oscilloscope and this is my SPI bitbang that works

Blue is the clock and yellow is the mosi of 0x8f (read whoami)

Blue is the clock and yellow is the chip select

------

Now the part that doesn't work, from the nordic sdk api call to spi.

Please note that this is on MODE 0.

nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
spi_config.ss_pin    = SPI_SS_PIN;
spi_config.miso_pin  = SPI_MISO_PIN;
spi_config.mosi_pin  = SPI_MOSI_PIN;
spi_config.sck_pin   = SPI_SCK_PIN;
spi_config.frequency = NRF_SPI_FREQ_125K;
spi_config.bit_order = NRF_DRV_SPI_BIT_ORDER_MSB_FIRST;
spi_config.mode      = NRF_DRV_SPI_MODE_0;

Blue is the clock and yellow is the mosi of 0x8f (read whoami)

Blue is clock and yellow is the chip select

Blue is the clock and yellow is the mosi of {0x8f,0xff} (read whoami), like hmolesworth suggested

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

hmolesworth — Thu, 26 Apr 2018 19:35:01 GMT

Ah-Ha! Try reading .. use 0x8F not 0x0F .. similar to this - or did you try that I now notice above

    uint8_t tx_buf[] = {0x80|LIS2DH12_WHO_AM_I, 0xFF};

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

RenatoMorelli — Thu, 26 Apr 2018 19:02:36 GMT

Sorry, my bad. I did try mode 0, which is the default one.

I slightly modified the SPI example in SDK 14.2, here how it looks like.

0x0F is the WHO_AM_I register, and I tried too 0X8F (bit 7 high for read operation).

I really appreciate your help, thanks hmolesworth. There are a few other threads about this same problem here in the devzone.

#include "nrf_drv_spi.h"
#include "app_util_platform.h"
#include "nrf_gpio.h"
#include "nrf_delay.h"
#include "boards.h"
#include "app_error.h"
#include <string.h>
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#include "nrf_gpio.h"

#define SPI_INSTANCE  0 /**< SPI instance index. */
static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */
static volatile bool spi_xfer_done;  /**< Flag used to indicate that SPI instance completed the transfer. */

// according to sdk_config.h
//SPI0_ENABLED 1
//SPI0_USE_EASY_DMA 1
//SPI_SCK_PIN 3
//SPI_MISO_PIN 28
//SPI_MOSI_PIN 4
//SPI_SS_PIN 29

//#define TEST_STRING "Nordic"
static uint8_t       m_tx_buf[] = {0x0F,0x00};           /**< TX buffer. */
static uint8_t       m_rx_buf[] = {0x00,0x00};    /**< RX buffer. */
static const uint8_t m_length = sizeof(m_tx_buf);        /**< Transfer length. */

/**
 * @brief SPI user event handler.
 * @param event
 */
void spi_event_handler(nrf_drv_spi_evt_t const * p_event,
                       void *                    p_context)
{
    spi_xfer_done = true;
    NRF_LOG_INFO("Transfer completed.");
    if (m_rx_buf[0] != 0)
    {
        NRF_LOG_INFO(" Received:");
        NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));
    }
}

int main(void)
{
    bsp_board_leds_init();

    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();
    
    NRF_LOG_INFO("SPI example.");

    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
    spi_config.ss_pin    = SPI_SS_PIN;
    spi_config.miso_pin  = SPI_MISO_PIN;
    spi_config.mosi_pin  = SPI_MOSI_PIN;
    spi_config.sck_pin   = SPI_SCK_PIN;
    spi_config.frequency = NRF_SPI_FREQ_125K;
    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));

    while (1)
    {
        // Reset rx buffer and transfer done flag
        memset(m_rx_buf, 0, m_length);
        spi_xfer_done = false;

        bsp_board_led_invert(BSP_BOARD_LED_0);
        
        APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, 2, m_rx_buf, 2));

        while (!spi_xfer_done)
        {
            __WFE();
        }

        NRF_LOG_FLUSH();

        bsp_board_led_invert(BSP_BOARD_LED_0);
        nrf_delay_ms(1000);
    }
}

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

hmolesworth — Thu, 26 Apr 2018 18:58:39 GMT

I just noticed something: Product Spec v3.3 SPI Max frequency is listed at 4MHz; I see you are using 8MHz

fSCK SCK frequency. 0.125 4 MHz

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

hmolesworth — Thu, 26 Apr 2018 18:48:14 GMT

You tried modes 1,2,3 but did you try mode 0? I use mode 0 with the similar part. Maybe post your code again is case we can spot something ..

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

RenatoMorelli — Thu, 26 Apr 2018 18:22:58 GMT

Ok, MOSI and MISO, sorry for the inaccurate terminology.

I managed to make the I2C (or TWI) work, but I need to do it with the SPI and the SDK functions are not working for me.

I even did a bit-bang for the SPI and it worked, but I need help with the SDK SPI.

I checked on the oscilloscope and CS in going low during communication window, MOSI is fine, CLK is fine, but get 0xFF on MISO when asking for WHO_AM_I. I initialized the SPI, tried modes 1 to 3, changed the data rate, enlarged the buffers (rx and tx with the same size), but I am still missing something :/

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

hmolesworth — Mon, 23 Apr 2018 22:23:23 GMT

There is no SDA or SDO signal on an SPI interface; SDA or SDO are only applicable to I2C which is a very different protocol being both more complex to implement and much slower in operation. There are examples for I2C and I2C fully supported by the Nordic libraries so perhaps search for those. Commonly I2C is used where multiple devices exist on a single 2-wire serial bus.

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

RenatoMorelli — Mon, 23 Apr 2018 21:23:42 GMT

Hi hmolesworth,

I did what you say, but I only get 0xFF :/

SPI 0 is enabled on config.

I checked some repos on the internet and the example on sdk 14.2, but no progress. When I change SDA and SDO, I get no response at all or 0xFF.

What could it be?

Thanks :D

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

hmolesworth — Sun, 25 Mar 2018 15:06:02 GMT

The SPI can't return the id you require using your code since the LIS doesn't know what the command is until after the 8-bit tx transfer is complete. If sending an 8-bit command that didn't require a response then a length of 1 byte transfer is fine, but you want the ID response so therefore you require a 2-byte transfer: 1st tx byte is request, 2nd a dummy 0. 1st Rx byte a dummy, 2nd a response to the Tx command request. In general the Rx stream is always 1-byte behind the tx stream since the first tx byte instructs the LIS what to put in the response.

I would stick with Mode 0 as that works .. also I would recommend finding the LIS in the examples, eg: look in Thingy SDK v2.1.0\include\frivers which can be downloaded from Nordic

/**@brief Read and verify accelerometer ID.
 */
static ret_code_t lis3dh_verify_id(void)
{
    ret_code_t  err_code;
    uint8_t     reg_val;

    err_code = lis3dh_read_regs(WHO_AM_I, &reg_val);
    RETURN_IF_ERROR(err_code);

    return (reg_val == I_AM_LIS3DH);
}

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

Agam — Sun, 25 Mar 2018 07:31:12 GMT

Hi,

Thanks for guiding. yeah, I am implementing SPI for first time, I increased the size of tx_buff to 5, and before sending I specify the correct length

 uint8_t rx_length = 1;        /**< Transfer length. */
        uint8_t tx_length = 1;
        
        spi_xfer_done = false;
        //STATIC_ASSERT(tx_length == rx_length);
        APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, tx_length, m_rx_buf, rx_length));
        while (!spi_xfer_done){
	  __WFE();
        }

static uint8_t m_tx_buf[]={0x0F, 0x00, 0x00, 0x00, 0x00}; /**< TX buffer. */
static uint8_t m_rx_buf[]={0x00, 0x00, 0x00, 0x00, 0x00}; /**< RX buffer. */

I kept the mode=2 because in datasheet of sensor is says " Those lines are driven at the falling edge of SPC and should be captured at the rising edge of SPC".

Output is still FF only.

Thank you for quick reply :)

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

hmolesworth — Sun, 25 Mar 2018 05:26:17 GMT

You have at least two problems: you might try SPI_MODE_0 instead of MODE_2, as that works correctly with the similar part LIS2DH12. Also if this is the first time you have used SPI, it's not obvious that to receive (say) 5 bytes that you actually have to transmit 5 bytes as the transmit provides the clock required for the receive. In the case above only 1 byte is transmitted, so increase that to 5

    spi_config.ss_pin    = ACC_CS_PIN;
    spi_config.miso_pin  = ACC_MISO_PIN;
    spi_config.mosi_pin  = ACC_MOSI_PIN;
    spi_config.sck_pin   = ACC_SCK_PIN;
    spi_config.frequency = NRF_SPI_FREQ_8M;
    spi_config.bit_order = NRF_DRV_SPI_BIT_ORDER_MSB_FIRST;
    spi_config.mode      = NRF_DRV_SPI_MODE_0;
    APP_ERROR_CHECK(nrf_drv_spi_init(&mAccSpiInstance, &spi_config, acc_spi_event_handler, NULL));

static uint8_t m_tx_buf[]={0x0F, 0x00, 0x00, 0x00, 0x00}; /**< TX buffer. */
static uint8_t m_rx_buf[]={0x00, 0x00, 0x00, 0x00, 0x00}; /**< RX buffer. */
static const uint8_t m_length = sizeof(m_rx_buf);       /**< Transfer length. */

// Ensure transmit and receive buffers are identical lengths
#include "nrf_drv_common.h";
STATIC_ASSERT(sizeof(m_rx_buf) == sizeof(m_tx_buf));

And now specify correct lengths:

// Ensure transmit and receive buffers are identical lengths
#include "nrf_drv_common.h";

// 2 bytes each or whatever ..
uint8_t sizerx = 2, sizerx = 2;

STATIC_ASSERT(sizetx == sizerx);

APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, sizetx, m_rx_buf, sizerx));

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

Agam — Sun, 25 Mar 2018 03:54:42 GMT

No, I dont have logic analyzer

Is there any other way to check ?

RE: Unable to interface nrf51822 with LIS3DH (accelerometer) using SPI being nrf as master

Jørgen Holmefjord — Fri, 23 Mar 2018 08:44:53 GMT

Hi,

Have you checked the SPI bus with a logic analyzer, to see if anything is actually transmitted/received?

Best regards,
Jørgen