ST STM32L4+ Series Reference Manual page 686

Analog-to-digital converters (ADC)
Where:
•
TS_CAL2 is the temperature sensor calibration value acquired at TS_CAL2_TEMP.
•
TS_CAL1 is the temperature sensor calibration value acquired at TS_CAL1_TEMP.
•
TS_DATA is the actual temperature sensor output value converted by ADC.
Refer to the device datasheet for more information about TS_CAL1 and TS_CAL2
calibration points.
Note: The sensor has a startup time after waking from power-down mode before it can output V
at the correct level. The ADC also has a startup time after power-on, so to minimize the
delay, the ADEN and CH17SEL bits should be set at the same time.
The above formula is given for TS_DATA measurement done with the same V
as TS_CAL1/TS_CAL2 values. If V
example if V
be replaced by TS_DATA x (3.3/3.0).
21.4.33 V supply monitoring
BAT
The CH18SEL bit in the ADCx_CCR register is used to switch to the battery voltage. As the
V voltage could be higher than V
BAT
V pin is internally connected to a bridge divider by 3. This bridge is automatically enabled
BAT
when CH18SEL is set, to connect V
converted digital value is one third of the V
consumption on the battery, it is recommended to enable the bridge divider only when
needed, for ADC conversion.
Refer to the electrical characteristics of the device datasheet for the sampling time value to
be applied when converting the V
The figure below shows the block diagram of the V
1. The CH18SEL bit must be set to enable the conversion of internal channel for V
686/2301
= 3.3 V and TS_CAL data are acquired at V
REF+
BAT
Figure 156. V
V
BAT
V
BAT
RM0432 Rev 6
is different, the formula must be adapted. For
REF+
, to ensure the correct operation of the ADC, the
DDA
/3 to the ADC input channels. As a consequence, the
BAT
voltage. To prevent any unwanted
BAT
/3 voltage.
sensing feature.
BAT
channel block diagram
BAT
CH18SEL control bit
/3
ADC input
= 3.0 V, TS_DATA must
REF+
ADCx
/3.
BAT
RM0432
TS
voltage
REF+
MSv37245V1