Analog-to-digital converters (ADC)
RM0365
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DocID025202 Rev 7
ADCx_CALFACT register without recalibrating, supposing that the software has previously
saved the calibration factor delivered during the previous calibration.
The calibration factor can be written if the ADC is enabled but not converting (ADEN=1 and
ADSTART=0 and JADSTART=0). Then, at the next start of conversion, the calibration factor
will automatically be injected into the analog ADC. This loading is transparent and does not
add any cycle latency to the start of the conversion.
Software procedure to calibrate the ADC
1.
Ensure ADVREGEN[1:0]=01 and that ADC voltage regulator startup time has elapsed.
2. Ensure that ADEN=0.
3. Select the input mode for this calibration by setting ADCALDIF=0 (Single-ended input)
or ADCALDIF=1 (Differential input).
4. Set
ADCAL=1.
5. Wait until ADCAL=0.
6. The calibration factor can be read from ADCx_CALFACT register.
Figure 54. ADC calibration
Software procedure to re-inject a calibration factor into the ADC
1.
Ensure ADEN=1 and ADSTART=0 and JADSTART=0 (ADC enabled and no
conversion is ongoing).
2. Write CALFACT_S and CALFACT_D with the new calibration factors.
3. When a conversion is launched, the calibration factor will be injected into the analog
ADC only if the internal analog calibration factor differs from the one stored in bits
CALFACT_S for single-ended input channel or bits CALFACT_D for differential input
channel.
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