ST STM32L4+ Series Reference Manual page 624

Analog-to-digital converters (ADC)
ADC state
Internal
calibration factor[6:0]
Start conversion
(hardware or sofware)
WRITE ADC_CALFACT
CALFACT_S[6:0]
Converting single-ended and differential analog inputs with a single ADC
If the ADC is supposed to convert both differential and single-ended inputs, two calibrations
must be performed, one with ADCALDIF=0 and one with ADCALDIF=1. The procedure is
the following:
1. Disable the ADC.
2. Calibrate the ADC in single-ended input mode (with ADCALDIF=0). This updates the
register CALFACT_S[6:0].
3. Calibrate the ADC in differential input modes (with ADCALDIF=1). This updates the
register CALFACT_D[6:0].
4. Enable the ADC, configure the channels and launch the conversions. Each time there
is a switch from a single-ended to a differential inputs channel (and vice-versa), the
calibration will automatically be injected into the analog ADC.
Internal
calibration factor[6:0]
CALFACT_S[6:0] F2
CALFACT_D[6:0] F3
624/2301
Figure 93. Updating the ADC calibration factor
Ready (not converting)
F1
by s/w by h/w
Figure 94. Mixing single-ended and differential channels
Trigger event
CONV CH 1
RDY
ADC state
Single ended
inputs channel)
F2
Converting channel
(Single ended)
Updating calibration
F2
F2
RDY CONV CH2
(Differential
inputs channel)
F3
RM0432 Rev 6
Ready Converting channel
(Single ended)
RDY CONV CH3 RDY CONV CH4
(Differential
(Single inputs
inputs channel)
RM0432
MSv30529V2
channel)
F2
MSv30530V2