RM0453 Rev 1 537/1461
RM0453 Analog-to-digital converter (ADC)
592
Figure 59. ADC calibration
Calibration factor forcing Software Procedure
1. Ensure that ADEN = 1 and ADSTART = 0 (ADC started with no conversion ongoing)
2. Write ADC_CALFACT with the saved calibration factor
3. The calibration factor is used as soon as a new conversion is launched.
Figure 60. Calibration factor forcing
18.3.4 ADC on-off control (ADEN, ADDIS, ADRDY)
At power-up, the ADC is disabled and put in power-down mode (ADEN = 0).
As shown in Figure 61, the ADC needs a stabilization time of t
STAB
before it starts
converting accurately.
Two control bits are used to enable or disable the ADC:
• Set ADEN = 1 to enable the ADC. The ADRDY flag is set as soon as the ADC is ready
for operation.
• Set ADDIS = 1 to disable the ADC and put the ADC in power down mode. The ADEN
and ADDIS bits are then automatically cleared by hardware as soon as the ADC is fully
disabled.
Conversion can then start either by setting ADSTART to 1 (refer to Section 18.4: Conversion
on external trigger and trigger polarity (EXTSEL, EXTEN) on page 547) or when an external
trigger event occurs if triggers are enabled.
t
CAB
ADCAL
ADC State
ADC_DR[6:0]
0x00
MS33703V1
CALIBRATE
OFF
Startup
OFF
by S/W by H/W
CALIBRATION
FACTOR
ADC_CALFACT[6:0]
ADC state
F2
F1
F2
Ready (not converting) Converting channel Ready Converting channel
(Single ended) (Single ended)
Updating
calibration
MS31925V1
by S/W
Internal
calibration factor[6:0]
Start conversion
(hardware or software)
WRITE ADC_CALFACT
CALFACT[6:0]
by H/W
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