Wakeup BNO055 from suspend mode

[michael_sensor]

Hello 

I am using a BNO055 as a compass. This is my process:

- Initialisation (Power Mode Normal, Operation Mode NDOF, external Clock source)

- get calibration register (system, gyro, accel, mag) until they reach "3"

- get the euler heading angle

- go to suspend mode (first go to Config mode, then set Suspend Mode)

Now, what is the correct approach to wakeup the BNO from suspend mode? When I go to the Config mode first and change to Normal mode after, my calibration registers say "0" for all three sensors and the euler heading ist random... After a reset, the calibration registers instantly have a "3" again until I wake the BNO up again.

The BNO is always powered and not turned off.

And by the way whats the sys calib register? sometims all 3 sensors are fully calibrated and  the system register says "0".

Thanks for your help

Kind regards

Michael

[Vincent]

I will suggest to check the proper delay inside the code for each steps since you are able to achive correct output with step by step running.

[michael_sensor]

Hello again

the procedure to wake up the bno: Suspend Mode --> Config Mode --> NDOF Mode doesnt work in my case. I always have to do Suspend --> Config --> Normal Power Mode --> NDOF. Is this normal? It seems like the error comes from the wake up function but im struggling to find the reason.

this is my function:

void wakeup_bno(void){

/* _First set Config Mode! */
uint8_t reg[2] = {BNO055_OPR_MODE_ADDR, BNO055_OPERATION_MODE_CONFIG};
m_xfer_done = false;
twi_reg_write(BNO055_I2C_ADDR1, reg, 2);
nrf_delay_ms(650);

/* Enter Normal Mode to wake up*/
reg[0] = BNO055_PWR_MODE_ADDR; reg[1] = BNO055_POWER_MODE_NORMAL;
m_xfer_done = false;
twi_reg_write(BNO055_I2C_ADDR1, reg, 2);
nrf_delay_ms(650);

/* Operation Mode */
reg[0] = BNO055_OPR_MODE_ADDR; reg[1] = BNO055_OPERATION_MODE_NDOF;
m_xfer_done = false;
twi_reg_write(BNO055_I2C_ADDR1, reg, 2);
nrf_delay_ms(650);
}

[Vincent]

I will suggest you to have only two write of register in the wake up function:

/* Enter Normal Mode to wake up*/
reg[0] = BNO055_PWR_MODE_ADDR; reg[1] = BNO055_POWER_MODE_NORMAL;
m_xfer_done = false;
twi_reg_write(BNO055_I2C_ADDR1, reg, 2);
nrf_delay_ms(650);

/* Operation Mode */
reg[0] = BNO055_OPR_MODE_ADDR; reg[1] = BNO055_OPERATION_MODE_NDOF;
m_xfer_done = false;
twi_reg_write(BNO055_I2C_ADDR1, reg, 2);
nrf_delay_ms(650);