Access to temperature readout from LPS22HB

[sekocabas]

Hello,
LPS22HB includes a temperature sensor as well. Would you consider making the following additions to the library? I could send a pull request if you prefer.

// Addition to Baro.cpp
#define LPS22HB_TEMP_OUT_L_REG     0x2b
#define LPS22HB_TEMP_OUT_H_REG     0x2c

float LPS22HBClass::readTemperature()
{
  // trigger one shot
  i2cWrite(LPS22HB_CTRL2_REG, 0x01);

  // wait for completion
  while ((i2cRead(LPS22HB_STATUS_REG) & 0x02) == 0) {
    yield();
  }

  int16_t temp_int = (i2cRead(LPS22HB_TEMP_OUT_L_REG) |
          (i2cRead(LPS22HB_TEMP_OUT_H_REG) << 8));
  float reading =  temp_int/ 100.0;

  return reading;
}

// Addition to Baro.h
float readTemperature();

Also, there is a temperature sensor within the nRF52840 controller of Nano 33 BLE Sense. The following code snippet (a bunch of copy-pasted lines from the indicated URLs) allows access to that register. It may perhaps be useful to those who are trying to access the nRF52840 internals.

// read the ARM chip in-built TEMP register
// See https://infocenter.nordicsemi.com/topic/ps_nrf52840/temp.html?cp=4_0_0_5_27
int32_t volatile temp_builtin;
float temp_builtin_float;

// The following is from https://github.com/particle-iot/nrf5_sdk/blob/master/modules/nrfx/hal/nrf_temp.h
#define MASK_SIGN           (0x00000200UL)
#define MASK_SIGN_EXTENSION (0xFFFFFC00UL)

// Initialization of temp
// Equivalent to 'nrf_temp_init();' call in main.c below, copied from nrf_temp.h
/**@note Workaround for PAN_028 rev2.0A anomaly 31 - TEMP: Temperature offset value has to be manually loaded to the TEMP module */
*(uint32_t *) 0x4000C504 = 0;

// from https://github.com/particle-iot/nrf5_sdk/blob/master/examples/peripheral/temperature/main.c
NRF_TEMP->TASKS_START = 1; /** Start the temperature measurement. */
// Wait until measurement done
while (NRF_TEMP->EVENTS_DATARDY == 0)
{
    // Do nothing.
}
NRF_TEMP->EVENTS_DATARDY = 0;

/**@note Workaround for PAN_028 rev2.0A anomaly 28 - TEMP: Negative measured values are not represented correctly */
temp_builtin = ((NRF_TEMP->TEMP & MASK_SIGN) != 0) ? (int32_t)(NRF_TEMP->TEMP | MASK_SIGN_EXTENSION) : (NRF_TEMP->TEMP);

/**@note Workaround for PAN_028 rev2.0A anomaly 30 - TEMP: Temp module analog front end does not power down when DATARDY event occurs. */
NRF_TEMP->TASKS_STOP = 1; /** Stop the temperature measurement. */

// Convert temp_builtin to degC
temp_builtin_float = temp_builtin * 0.25f;