2.9.3 Temperature Measurement

When triggering a temperature measurement, the AD converter of the ATA8510/15 operates as a temperature sensor in the range of -40°C to +125°C with a resolution of 1K. The temperature is measured on a specific temperature measurement channel with fLO = 422 MHz. The result of the AD converter is provided in the TEMPH and TEMPL hardware registers, then copied to the calib.sramTEMPH/L SRAM variables by the firmware.

In a subsequent step, a temperature value is calculated and stored to the calib.tempMeas SRAM variable. The valid range of tempMeas is 0 to 175. The actual temperature in °C can be calculated based on the following formula:

T = tempMeas - 50......(2)

Equation parameters:

T – Current temperature [°C]

tempMeas – Content of the calib.tempMeas SRAM variable

Address

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

0x02D9

sramTEMPH

Temperature high byte

0x02DA

sramTEMPL

Temperature low byte

0x02DB

tempMeas

8-bit temperature measurement result (valid range 0..175)

The result of the calculation is used as input for the XTO temperature compensation (RF calibration), as described in RF Calibration.

The “Read SRAM/Register” SPI command can be used to read out the calculated temperature from the calib.tempMeas SRAM variable.

A temperature measurement process can be triggered at the following time points:

  • After power-on during system initialization when enabled in eepConfValid.confInitFlags.TempMeas.

Address

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

0x0008

confInitFlags

AntTune

TempMeas

SRC

FRC

————
  • During the periodic self-check in PollingMode or during a self-check that is started by using the “Calibrate and Check” SPI command if enabled in eepTrxCal.calConf1.EN_TEMP_MEAS.
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x001C calConf1 —EN_TEMP_MEAS EN_SRCCAL EN_FRCCAL ———EN_REGREFRESH
  • From IDLEMode via the “Calibrate and Check” SPI command if bit EN_TEMP_MEAS in tuneCheckConfig is set to ‘1’, see Calibrate and Check.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
tuneCheckConfig EN_ANT_TUNE EN_TEMP_MEAS EN_SRCCAL EN_FRCCAL EN_VCOCAL —EN_SELFCHECK —

Setting the TEMP_MEAS bit within the eepEventConf.cmdRdyConf command-ready variable to ‘1’ raises a command-ready (CMD_RDY) event on the PB6 event pin when the temperature measurement process has finished.

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x0096 cmdRdyConf ANT_TUNE TEMP_MEAS SRC_CAL FRC_CAL VCO_CAL RF_CAL SELFCHECK TX

The temperature measurement requires additional time, see Timing Characteristics.