Temperature Sensor; Internal Voltage Reference; Refint; Vbat - STMicroelectronics STM32F038C6 Manual

Functional overview
An analog watchdog feature allows very precise monitoring of the converted voltage of one,
some or all selected channels. An interrupt is generated when the converted voltage is
outside the programmed thresholds.
3.10.1

Temperature sensor

The temperature sensor (TS) generates a voltage V
temperature.
The temperature sensor is internally connected to the ADC_IN16 input channel which is
used to convert the sensor output voltage into a digital value.
The sensor provides good linearity but it has to be calibrated to obtain good overall
accuracy of the temperature measurement. As the offset of the temperature sensor varies
from chip to chip due to process variation, the uncalibrated internal temperature sensor is
suitable for applications that detect temperature changes only.
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.
Calibration value name
3.10.2 Internal voltage reference (V
The internal voltage reference (V
ADC. V

REFINT

of V
REFINT
the system memory area. It is accessible in read-only mode.
Calibration value name
VREFINT_CAL
3.10.3 V battery voltage monitoring
BAT
This embedded hardware feature allows the application to measure the V
using the internal ADC channel ADC_IN18. As the V
and thus outside the ADC input range, the V
divider by 2. As a consequence, the converted digital value is half the V
16/102

Table 3. Temperature sensor calibration values

TS ADC raw data acquired at a
TS_CAL1 temperature of 30 °C (± 5 °C),
V
TS ADC raw data acquired at a
TS_CAL2 temperature of 110 °C (± 5 °C),
V
is internally connected to the ADC_IN17 input channel. The precise voltage
is individually measured for each part by ST during production test and stored in

Table 4. Internal voltage reference calibration values

Raw data acquired at a
temperature of 30 °C (± 5 °C),
V
DDA
DocID026079 Rev 3
SENSE
Description
= 3.3 V (± 10 mV)
DDA
= 3.3 V (± 10 mV)
DDA
)
REFINT
) provides a stable (bandgap) voltage output for the
REFINT
Description
= 3.3 V (± 10 mV)
BAT
pin is internally connected to a bridge
BAT
STM32F038x6
that varies linearly with
Memory address
0x1FFF F7B8 - 0x1FFF F7B9
0x1FFF F7C2 - 0x1FFF F7C3
Memory address
0x1FFF F7BA - 0x1FFF F7BB
battery voltage
BAT
voltage may be higher than V
voltage.
BAT
,
DDA