TWI no data from Sensor

Question

I have a temperature/humidity sensor from Sensirion. The Type is SHT21x. The sensor has I2C so it should be able to tranfer the data from the sensor to the Nordic chip over I2C. I`m working with the nRF51DK. The sensor works fine. I wrote my own I2C protocol with bit banging and both measurements did what they should. Now I want to use the soft device, because later I would like to send the data to a mobile device. So I tried to get it work with the twi_hw_master example.

SoftDevice 8.0.0 is flashed on the chip.

The measurement for the humidity works fine! But when I try to read the temperature I wont get data from the sensor. But I do get the ACK when I send the read command for the temperature.

I have a case open on nordic support but for days the problem wont get fixed. Maybe somebody worked with the sensor from Sensiron and had the same problem?

Below my code:

static void timer_timeout_handler()
{
 hum_temp = !hum_temp;
 if(hum_temp == true)
 {
	nrf_gpio_pin_toggle(24);
	twi_master_transfer(0x80, &hm_hum, 1,0);
	twi_master_transfer(0x81, hum_data,3,1);
	nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT1, *hum_data);
 }
 else
 {
	nrf_gpio_pin_toggle(23);
	twi_master_transfer(0x80, &hm_temp, 1,0);
	twi_master_transfer(0x81, temp_data,3,1);
	nrf_gpio_port_write(NRF_GPIO_PORT_SELECT_PORT1, *temp_data);
 }
}

Every 2 seconds I will jump in the timer_timeout_ handler() routine.

Here the read function:

static bool twi_master_read(uint8_t *data, uint8_t data_length, bool issue_stop_condition)
{
    uint32_t timeout = MAX_TIMEOUT_LOOPS;   /* max loops to wait for RXDREADY event*/

if (data_length == 0)
{
    /* Return false for requesting data of size 0 */
    NRF_TWI1->SHORTS = 0; //short are not enabled yet, may not be necessary
    return false;
}
else if (data_length == 1)
{
    NRF_TWI1->SHORTS = TWI_SHORTS_BB_STOP_Enabled << TWI_SHORTS_BB_STOP_Pos;
}
else
{
    NRF_TWI1->SHORTS = TWI_SHORTS_BB_SUSPEND_Enabled << TWI_SHORTS_BB_SUSPEND_Pos;
}

NRF_TWI1->EVENTS_RXDREADY = 0;
NRF_TWI1->TASKS_STARTRX   = 1;

/** @snippet [TWI HW master read] */
while (true)
{
    while(NRF_TWI1->EVENTS_RXDREADY == 0 && NRF_TWI1->EVENTS_ERROR == 0 && (--timeout))
    {
        // Do nothing.
    }
    NRF_TWI1->EVENTS_RXDREADY = 0;

    if (timeout == 0 || NRF_TWI1->EVENTS_ERROR != 0)
    {
      // Recover the peripheral as indicated by PAN 56: "TWI: TWI module lock-up." found at
      // Product Anomaly Notification document found at
      // www.nordicsemi.com/.../
      NRF_TWI1->EVENTS_ERROR = 0;
      NRF_TWI1->ENABLE       = TWI_ENABLE_ENABLE_Disabled << TWI_ENABLE_ENABLE_Pos;
      NRF_TWI1->POWER        = 0;
      nrf_delay_us(5);
      NRF_TWI1->POWER        = 1;
      NRF_TWI1->ENABLE       = TWI_ENABLE_ENABLE_Enabled << TWI_ENABLE_ENABLE_Pos;

      (void)twi_master_init();

      NRF_TWI1->SHORTS = 0;
      return false;
    }

    *data++ = NRF_TWI1->RXD;

    if (--data_length == 1)
    {
        NRF_TWI1->SHORTS = TWI_SHORTS_BB_STOP_Enabled << TWI_SHORTS_BB_STOP_Pos;
    }

    if (data_length == 0)
    {
        break;
    }

    // Recover the peripheral as indicated by PAN 56: "TWI: TWI module lock-up." found at
    // Product Anomaly Notification document found at
    // www.nordicsemi.com/.../
    nrf_delay_us(20);
    NRF_TWI1->TASKS_RESUME = 1;
}
/** @snippet [TWI HW master read] */

/* Wait until stop sequence is sent */
while(NRF_TWI1->EVENTS_STOPPED == 0)
{
    // Do nothing.
}
NRF_TWI1->EVENTS_STOPPED = 0;

NRF_TWI1->SHORTS = 0;
	
return true;
}

I need to know how to fix this problem.

Alex · Accepted Answer

#define MAX_TIMEOUT_LOOPS (10000UL) /*!< MAX while loops to wait for RXD/TXD event */
 
 Don't know how much it is in ms. Try to increase to maximum possible or comment out timeout code for now.

TWI no data from Sensor

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