Read data from sensor i2c

RE: Read data from sensor i2c

Francis — Tue, 04 Aug 2015 16:51:22 GMT

Thanks, your help has been very useful!

RE: Read data from sensor i2c

Alex — Tue, 04 Aug 2015 11:00:01 GMT

For STOP condition look at BNO055 datasheet page 92. It is common for all I2C devices

RE: Read data from sensor i2c

Francis — Tue, 04 Aug 2015 10:15:21 GMT

The solution is changing the Operating Mode to 0x00 and after, setting a Operating Mode. Now, it changes the Operating Mode fine, but it doesn't read data.

Can you explain me when I have to set issue_stop_condition to 0 or 1?

<// Change Operating Mode uint8_t dataW[2] = {0x3D, 0x0C}; uint8_t dataW_0[2] = {0x3D, 0x00};

twi_master_transfer(0X52,dataW_0,2,1); nrf_delay_us(4000);

twi_master_transfer(0X52,dataW,2,0); nrf_delay_us(4000);

// Read all data (accel, magnetometer and gyroscope). dataW[0] = 0x08; twi_master_transfer(0x52,dataW,1,0); twi_master_transfer(addR,dataR,18,1);

// Read Operating Mode dataW[0] = 0x3D; twi_master_transfer(0x52,dataW,1,0); twi_master_transfer(addR,estado,1,1); <>

RE: Read data from sensor i2c

Francis — Tue, 04 Aug 2015 09:41:51 GMT

The same, it only changes the Operating Mode when I turn off the board and after, I turn on the board again...

I try change the code (uint8_t dataW[2] = {0x3D, 0x02}; instead of uint8_t dataW[2] = {0x3D, 0x01}; for example) to change the Operating Mode, but it doesn't work whitout turning off the board.

RE: Read data from sensor i2c

Alex — Tue, 04 Aug 2015 09:22:56 GMT

Write sequence should be

twi_master_transfer(,,,1);

Read sequence:

twi_master_transfer(,,1,0); 
twi_master_transfer(,,,1);

RE: Read data from sensor i2c

Francis — Tue, 04 Aug 2015 09:14:22 GMT

It doesn't work. It doesn't change the operating mode. It only changes the operating mode when I turn off the board.

<// Write Operating Mode uint8_t dataW[2] = {0x3D, 0x01}; twi_master_transfer(0X52,dataW,2,0);

// Read all data (accel, magnetometer and gyroscope). dataW[0] = 0x08; twi_master_transfer(0x52,dataW,1,0); twi_master_transfer(addR,dataR,18,1);

// Read Operating Mode dataW[0] = 0x3D; twi_master_transfer(0x52,dataW,1,0); twi_master_transfer(addR,estado,1,1); <>

RE: Read data from sensor i2c

Francis — Mon, 03 Aug 2015 11:18:51 GMT

Hi,

I've been testing the sensor but there is a thing it's doesn't work fine. BNO055 Sensor read data depending on an operating mode.

In my code, I set the Operating Mode to 0x01(ACCONLY). Sensor only should read accel data, but it read data of magnetometer and gyroscope. After, I read the operating mode register and his value is 0x0C (NDOF Mode)

My code is the next one:

	while(true){
			uint8_t addR = (0x52)|0x01; 
			uint8_t dataW[2] = {0x3D, 0x02}; 
			uint8_t dataR[18] = {0x00};
			uint8_t estado[1] = {0x00};
		

			twi_master_transfer(0X52,dataW,2,1);
			nrf_delay_us(400); 
			
			dataW[0] = 0x08;

			twi_master_transfer(0x52,dataW,1,1);

			
			uint16_t contador = 0;
			
			for(contador = 0; contador < 18; contador++){
			dataR[contador] = 0;
			}
			
			twi_master_transfer(addR,dataR,18,1); 
		
			printf("\n\rAccelX L: %d\n\r",dataR[0]);
			printf("\n\rAccelX M: %d\n\r",dataR[1]);
			printf("\n\rAccelY L: %d\n\r",dataR[2]);
			printf("\n\rAccelY M: %d\n\r",dataR[3]);
			printf("\n\rAccelZ L: %d\n\r",dataR[4]);
			printf("\n\rAccelZ M: %d\n\r",dataR[5]);
			printf("\n\rMagX L: %d\n\r",dataR[6]);
			printf("\n\rMagX M: %d\n\r",dataR[7]);
			printf("\n\rMagY L: %d\n\r",dataR[8]);
			printf("\n\rMagY M: %d\n\r",dataR[9]);
			printf("\n\rMagZ L: %d\n\r",dataR[10]);
			printf("\n\rMagZ M: %d\n\r",dataR[11]);
			printf("\n\rGirX L: %d\n\r",dataR[12]);
			printf("\n\rGirX M: %d\n\r",dataR[13]);
			printf("\n\rGirY L: %d\n\r",dataR[14]);
			printf("\n\rGirY M: %d\n\r",dataR[15]);
			printf("\n\rGirZ L: %d\n\r",dataR[16]);
			printf("\n\rGirZ M: %d\n\r",dataR[17]);
			
			dataW[0] = 0x3D;
			twi_master_transfer(0x52,dataW,1,1);
			twi_master_transfer(addR,estado,1,1); 
			printf("\n\rEstado: %X\n\r",estado[0]);
			nrf_delay_us(1000000);		
	
	}

RE: Read data from sensor i2c

Susheel Nuguru — Tue, 21 Jul 2015 12:03:31 GMT

Francis, could you please update this thread with latest info, if this answer helped you then please click the ✓ to the left of the answer so that others can come and look here.

RE: Read data from sensor i2c

wlgrd — Sun, 21 Jun 2015 22:14:17 GMT

Why don't you set it to the K400 macro then? And did you just say you got things to work?

RE: Read data from sensor i2c

Francis — Sun, 21 Jun 2015 21:57:14 GMT

Hi,

I've changed the frequency and it seems that works fine, but I need 400khz and I've set this value:

<> NRF_TWI1->FREQUENCY = TWI_FREQUENCY_FREQUENCY_K100 << TWI_FREQUENCY_FREQUENCY_Pos; <>

Thanks

RE: Read data from sensor i2c

wlgrd — Sun, 21 Jun 2015 21:37:37 GMT

Also, I see from the SDK

#define TWI_FREQUENCY_FREQUENCY_K100 (0x01980000UL) /*!< 100 kbps. */
#define TWI_FREQUENCY_FREQUENCY_K250 (0x04000000UL) /*!< 250 kbps. */
#define TWI_FREQUENCY_FREQUENCY_K400 (0x06680000UL) /*!< 400 kbps. */

and your way of setting the frequency is not correct.

RE: Read data from sensor i2c

wlgrd — Sun, 21 Jun 2015 21:28:10 GMT

I would advise trying higher resistor values, so the SoC don't need to sink so much current in order to properly pull the lines low. Can you retry with e.g 8-10k just to leave that out of the question? It should be ablet to sink the required 3.3mA, but just to make sure...

RE: Read data from sensor i2c

Francis — Sun, 21 Jun 2015 20:56:19 GMT

Pullups are 1k

RE: Read data from sensor i2c

wlgrd — Sun, 21 Jun 2015 18:48:55 GMT

Again, size of external pullups?

RE: Read data from sensor i2c

Francis — Sun, 21 Jun 2015 08:31:57 GMT

I've tested with internal pull up and without internal pull up. Pin 07 (SCL) and 30 (SDA) are always "1". I don't find the problem...

<> static bool twi_master_clear_bus(void) { uint32_t twi_state; bool bus_clear; uint32_t clk_pin_config; uint32_t data_pin_config;

// Save and disable TWI hardware so software can take control over the pins.
twi_state        = NRF_TWI1->ENABLE;
NRF_TWI1->ENABLE = TWI_ENABLE_ENABLE_Disabled << TWI_ENABLE_ENABLE_Pos;

clk_pin_config = \
    NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER_2];
NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER] =      \
    (GPIO_PIN_CNF_SENSE_Disabled  << GPIO_PIN_CNF_SENSE_Pos) \
  | (GPIO_PIN_CNF_DRIVE_S0D1    << GPIO_PIN_CNF_DRIVE_Pos)   \

/* | (GPIO_PIN_CNF_PULL_Pullup << GPIO_PIN_CNF_PULL_Pos) \ */ | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos);

data_pin_config = \
    NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_DATA_PIN_NUMBER_2];
NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_DATA_PIN_NUMBER] =       \
    (GPIO_PIN_CNF_SENSE_Disabled  << GPIO_PIN_CNF_SENSE_Pos) \
  | (GPIO_PIN_CNF_DRIVE_S0D1    << GPIO_PIN_CNF_DRIVE_Pos)   \

/* | (GPIO_PIN_CNF_PULL_Pullup << GPIO_PIN_CNF_PULL_Pos) \ */ | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos);

TWI_SDA_HIGH();
TWI_SCL_HIGH();
TWI_DELAY();

if ((TWI_SDA_READ() == 1) && (TWI_SCL_READ() == 1))
{
    bus_clear = true;
}
else
{
    uint_fast8_t i;
    bus_clear = false;

    // Clock max 18 pulses worst case scenario(9 for master to send the rest of command and 9
    // for slave to respond) to SCL line and wait for SDA come high.
    for (i=18; i--;)
    {
        TWI_SCL_LOW();
        TWI_DELAY();
        TWI_SCL_HIGH();
        TWI_DELAY();

        if (TWI_SDA_READ() == 1)
        {
            bus_clear = true;
            break;
        }
    }
}

NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER_2] = clk_pin_config;
NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_DATA_PIN_NUMBER_2]  = data_pin_config;

NRF_TWI1->ENABLE = twi_state;

return bus_clear;

}

bool twi_master_init_2(void) { /* To secure correct signal levels on the pins used by the TWI master when the system is in OFF mode, and when the TWI master is disabled, these pins must be configured in the GPIO peripheral. / NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER] =
(GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)
| (GPIO_PIN_CNF_DRIVE_S0D1 << GPIO_PIN_CNF_DRIVE_Pos)
/ | (GPIO_PIN_CNF_PULL_Pullup << GPIO_PIN_CNF_PULL_Pos) \ */ | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);

NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_DATA_PIN_NUMBER] =      \
    (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos) \
  | (GPIO_PIN_CNF_DRIVE_S0D1     << GPIO_PIN_CNF_DRIVE_Pos) \

/* | (GPIO_PIN_CNF_PULL_Pullup << GPIO_PIN_CNF_PULL_Pos) \ */ | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos)
| (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos);

NRF_TWI1->EVENTS_RXDREADY = 0;
NRF_TWI1->EVENTS_TXDSENT  = 0;
NRF_TWI1->PSELSCL         = TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER_2;
NRF_TWI1->PSELSDA         = TWI_MASTER_CONFIG_DATA_PIN_NUMBER_2;
NRF_TWI1->FREQUENCY       = 400000; //TWI_FREQUENCY_FREQUENCY_K100 << TWI_FREQUENCY_FREQUENCY_Pos
NRF_PPI->CH[0].EEP        = (uint32_t)&NRF_TWI1->EVENTS_BB;
NRF_PPI->CH[0].TEP        = (uint32_t)&NRF_TWI1->TASKS_SUSPEND;
NRF_PPI->CHENCLR          = PPI_CHENCLR_CH0_Msk;
NRF_TWI1->ENABLE          = TWI_ENABLE_ENABLE_Enabled << TWI_ENABLE_ENABLE_Pos;

return twi_master_clear_bus();

} <>

RE: Read data from sensor i2c

wlgrd — Sat, 20 Jun 2015 23:08:25 GMT

Size of Rpull1/2? And I guess there's no reason for internal pull-up on your pins when you have external ones. I guess the internal pullups also might break your circuitry since they they will be connected in parallell with the external pullups