Datasheet

DocID027100 Rev 4 29/149
STM32L072xx Functional overview
36
To improve the accuracy of the temperature sensor measurement, each device is
individually factory-calibrated by ST. The temperature sensor factory calibration data are
stored by ST in the system memory area, accessible in read-only mode.
3.12.1 Internal voltage reference (V
REFINT
)
The internal voltage reference (V
REFINT
) provides a stable (bandgap) voltage output for the
ADC and Comparators. V
REFINT
is internally connected to the ADC_IN17 input channel. It
enables accurate monitoring of the V
DD
value (when no external voltage, V
REF+
, is available
for ADC). The precise voltage of V
REFINT
is individually measured for each part by ST during
production test and stored in the system memory area. It is accessible in read-only mode.
3.13 Digital-to-analog converter (DAC)
Two 12-bit buffered DACs can be used to convert digital signal into analog voltage signal
output. An optional amplifier can be used to reduce the output signal impedance.
This digital Interface supports the following features:
• One data holding register (for each channel)
• Left or right data alignment in 12-bit mode
• Synchronized update capability
• Noise-wave generation
• Triangular-wave generation
• Dual DAC channels with independent or simultaneous conversions
• DMA capability (including the underrun interrupt)
• External triggers for conversion
• Input reference voltage V
REF+
Six DAC trigger inputs are used in the STM32L072xx. The DAC channels are triggered
through the timer update outputs that are also connected to different DMA channels.
Table 7. Temperature sensor calibration values
Calibration value name Description Memory address
TSENSE_CAL1
TS ADC raw data acquired at
temperature of 30 °C,
V
DDA
= 3 V
0x1FF8 007A - 0x1FF8 007B
TSENSE_CAL2
TS ADC raw data acquired at
temperature of 130 °C
V
DDA
= 3 V
0x1FF8 007E - 0x1FF8 007F
Table 8. Internal voltage reference measured values
Calibration value name Description Memory address
VREFINT_CAL
Raw data acquired at
temperature of 25 °C
V
DDA
= 3 V
0x1FF8 0078 - 0x1FF8 0079
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