BMI270 initialization problem with nRF52840

[Shinicy99]

Hello everyone, as i read in other topic on this forum i am also struggling to use BMI270 sensor, especially for initialization process.

I'm using nRF52840 SoC and i connected it to the IMU by using twi/i2c intarface. 

Here i attach my code for initialization:

//INIT FUNCTION FOR BMI270
bool BMI270_init(void)
{
  bool init_succ=true;
  
  //following datasheet  
  if(!BMI270_verify_product_id())
  {
   init_succ=false;
  }
  
  if(!BMI270_register_write(0x7C,0x00))
  {
    init_succ=false;
  }
  nrf_delay_us(800);
  if(!BMI270_register_write(0x59,0x00))
  {
    init_succ=false;
  }

// load configuration file from github repo
  while(BMI270_conf_file_init())
  {}

 if(!BMI270_register_write(0x59,0x01)){
    init_succ=false;// it seems that main problem is in this step
  }

  return init_succ;
}

 and these are the code for writing and reading registers:

bool BMI270_register_write(uint8_t register_address , uint8_t value)
{
  ret_code_t err_code;
  uint8_t tx_buff[BMI2_ADDRESS_LEN+1];

  tx_buff[0]=register_address;
  tx_buff[1]=value;

  m_xfer_done=false;

  //transimt data
  err_code=nrf_drv_twi_tx(&m_twi,BMI2_I2C_PRIM_ADDR,tx_buff,BMI2_ADDRESS_LEN+1,false);
  
  while(m_xfer_done==false)
  {
  }

  if(err_code != NRF_SUCCESS)
  {
    return false;
  }

  return true;
}

bool BMI270_register_read(uint8_t register_address,uint8_t *destination,uint8_t number_of_bytes)
{
  ret_code_t err_code;
  //flag for check receive
  m_xfer_done=false;
  //writing address we want to read
  err_code=nrf_drv_twi_tx(&m_twi,BMI2_I2C_PRIM_ADDR,&register_address,1,true);

  while(m_xfer_done==false){}
  
  if(err_code != NRF_SUCCESS)
  {
      return false;
  }

  m_xfer_done=false;
  //read data
  err_code=nrf_drv_twi_rx(&m_twi,BMI2_I2C_PRIM_ADDR,destination,number_of_bytes);

  while(m_xfer_done==false){}

   if(err_code != NRF_SUCCESS)
   {
      return false;
   }

   return true;
}

For burst write the config file i wrote an external function that rewrite on i2c bus the byte from config file:

bool BMI270_conf_file_init(void)
{
   uint8_t buff[2];
   int a;
   ret_code_t err_code;


   for(a=0;a<(sizeof(bmi270_context_config_file)-1);a++)
   {
     buff[0]=0x5E;
     buff[1]=bmi270_context_config_file[a];
     err_code=nrf_drv_twi_tx(&m_twi,BMI2_I2C_PRIM_ADDR,buff,2,true);
     while(m_xfer_done==false){}

    if(err_code != NRF_SUCCESS)
        {
            return false;
        }
  
           
   }
   
     buff[0]=0x5E;
     buff[1]=bmi270_context_config_file[sizeof(bmi270_context_config_file)-1];
     err_code=nrf_drv_twi_tx(&m_twi,BMI2_I2C_PRIM_ADDR,buff,2,false);
     while(m_xfer_done==false){}

    if(err_code != NRF_SUCCESS)
        {
            return false;
        }
   

   return true;
    
}

 The fact is that as i commented in the first code the initialization works until the last step where the function give me a false, also by bypassing that return false, it seems that reading the 0x5E register at the end of initialization the value does not correspond to the last byte of bmi270_context_config_file.

I know that are present on the github the API's for this sensor but i didn't understand how i can replace my writing and reading function to implement it.

Is there any way to overcome initialization burst write? And if it's not possible, how can i solve it?

PS: these are the declaration of the type fucntion used to write and read using twi of the SoC:

//reading function
ret_code_t nrf_drv_twi_rx	(	nrf_drv_twi_t const * 	p_instance,
uint8_t 	address,
uint8_t * 	p_data,
uint8_t 	length 
)	

//writing function

ret_code_t nrf_drv_twi_tx	(	nrf_drv_twi_t const * 	p_instance,
uint8_t 	address,
uint8_t const * 	p_data,
uint8_t 	length,
bool 	no_stop 
)	

[BSTRobin]

Hi Shinicy99,

You can fully refer to the BMI270 example code(https://github.com/boschsensortec/BMI270-Sensor-API/blob/master/bmi270_examples/accel_gyro/accel_gyr...), follow the example code procedure and replace the I2C read and write interface with the nRF52840 interface, and try again.

[Shinicy99]

Did you mean by replacing directly on code example bmi2.c:

dev->intf_rslt = dev->write((uint8_t)((uint16_t)reg_addr + loop), &data[loop], 1, dev->intf_ptr);

  on line 2038 for writing function and:

dev->intf_rslt = dev->read(reg_addr, temp_buf, (len + dev->dummy_byte), dev->intf_ptr);

 line 1980 for reading function with the one expressed for nrf?

There are others changes that i have to deal with? Because i didn't find any guide for using these API.

[BSTRobin]

Hi Shinicy99,

No. You don't need to modify bmi2.c.
I mean you can refer to accel_gyro.c which will call bmi2_interface_init() in the code. You can implement the content of this function based on your hardware platform.