I2C in nrf51 SDK

[rushin]

I want to interface ADXl345 with nrf51 SDK. suppoose my device address is 0x53 and register address is 0x2D and i want to write value 8. now nordic i2c has function nrf_drv_twi_tx with attributes nrf_drv_twi_t const *const p_instance, uint8_t address, uint8_t const * p_data, uint32_t length, bool xfer_pending

now here my address is 0x53, length is 6. now can you tell me where to write register address? where to write data??

[iamsheikhubaid]

I am trying to upload the code of bjorn-spockeli to NRF52 DK, but the code will stuck into a Fatal Error at these lines

ADXL375_I2C_data_rate_set(0x0A);
ADXL375_I2C_offsets_set(0,0,0);

Can any body explain, will it work for adxl 345 or have to change the register values or configurations. Thanks

[bjorn-spockeli]

The register map appears to be close to identical so i think it should work. Could you post the code you're running and a screenshot of the call stack when you get the error?

[iamsheikhubaid]

I am running the code of twi sensor, where I have added the adxl part,

here is the code of main

int main(void)
{

uint16_t a;
// nrf_delay_ms(1000);
APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
NRF_LOG_DEFAULT_BACKENDS_INIT();
ret_code_t ret_code;

ret_code = twi_master_init();

ADXL375_I2C_init(&m_twi_master);

int16_t x_val;
int16_t y_val;
int16_t z_val;
a=1;
NRF_LOG_INFO("A=%d",a);

ADXL375_I2C_data_rate_set(0x0A);
ADXL375_I2C_offsets_set(0,0,0);


APP_ERROR_CHECK(ret_code);

a=2;

while (1)
{
NRF_LOG_INFO("A=%d",a);
a=3;
//NRF_LOG_INFO("A=%d",a);

ADXL375_I2C_acc_data_read(&x_val,&y_val,&z_val);
NRF_LOG_INFO("A=%d",a);

NRF_LOG_INFO("x=%d, y=%d, z=%d",x_val,y_val,z_val);
//SEGGER_RTT_printf(0,"ACC DATA: X: %d Y: %d Z: %d \n", x_val ,y_val, z_val);
nrf_delay_ms(500);

// Do nothing.
}
}

it will print A=1

then comes a fatal error, here is the screen shot

 

Help me in this, Thanks

[bjorn-spockeli]

Why are you using a PCA10056(NRF52840 DK) Segger Embedded Studio project, when you state that you want to interface the ADXl345 with a nRF52 DK?

Also note that TWI driver used to make the ADXl345 was made for a 3 year old SDK and may not be compatible with the SDK version you are using? WHich version is it? Is it SDK v15.0.0 or newer?

[iamsheikhubaid]

I am currently using nRF_SDK_15.2.0, also i am usinng PCA10056 because its for nRF52840-DK like PCA10059 is for nRF52 Dongle. I have nRF52840 development kit so i have chosen PCA10056, Isn't it more or less similar with nRF52 DK, is there any main difference between nRF52 DK or nRF52840 DK? I just want to interface adxl-345 with my nRF52840 development kit using your library, but I am unable to get any values when I put these lines in the code.

ADXL375_I2C_data_rate_set(0x0A);
ADXL375_I2C_offsets_set(0,0,0);

also I have changed the SDA, SCL pins accordingly in TWI like

static ret_code_t twi_master_init(void)
{
ret_code_t ret;
const nrf_drv_twi_config_t config =
{
.scl = TWI_SCL_M,
.sda = TWI_SDA_M,
.frequency = NRF_TWI_FREQ_400K,
.interrupt_priority = APP_IRQ_PRIORITY_HIGH,
.clear_bus_init = false
};

do
{
ret = nrf_drv_twi_init(&m_twi_master, &config, twi_handler, NULL);
if(NRF_SUCCESS != ret)
{
break;
}
nrf_drv_twi_enable(&m_twi_master);
}while(0);
return ret;
}

where twi_handler is as

void twi_handler(nrf_drv_twi_evt_t const * p_event, void * p_context)
{
switch (p_event->type)
{
case NRF_DRV_TWI_EVT_DONE:
if (p_event->xfer_desc.type == NRF_DRV_TWI_XFER_RX)
{
ADXL375_I2C_acc_data_read(&x_val, &y_val, &z_val);
}
m_xfer_done = true;
break;
default:
break;
}
}

also I have defined SDA SCL pins according to the development kit, in the header file as

#define TWI_SCL_M 27 //!< Master SCL pin

#define TWI_SDA_M 26 //!< Master SDA pin
#define MASTER_TWI_INST 0 //!< MASTERTWI interface

/** I2C BUS ADRESSES*/
#define ADXL375_ADDR 0x53

/** REGISTER ADDRESSES */
#define DEVICE_ID 0x00
#define OFSX 0x1E
#define OFSY 0x1F
#define OFSZ 0x20

#define BW_RATE 0x2C
#define POWER_CTL 0x2D
#define DATAX0 0x32
#define DATAY0 0x34
#define DATAZ0 0x36

But still I  am not getting  cann't get any value. Can you help me out in this. Thanks

[iamsheikhubaid]

Hello Bjorn-spockeli, I am waiting for your response.

[bjorn-spockeli]

OK, are you able to capture a logic trace of the SDA and SCL lines going to the ADXL345 ?