
Analog-to-digital converter (ADC)
RM0453
574/1454
RM0453 Rev 2
Bit 2
ADSTART
: ADC start conversion command
This bit is set by software to start ADC conversion. Depending on the EXTEN [1:0] configuration bits,
a conversion either starts immediately (software trigger configuration) or once a hardware trigger
event occurs (hardware trigger configuration).
It is cleared by hardware:
– In single conversion mode (CONT = 0, DISCEN = 0), when software trigger is selected
(EXTEN = 00): at the assertion of the end of Conversion Sequence (EOS) flag.
– In discontinuous conversion mode(CONT = 0, DISCEN = 1), when the software trigger is selected
(EXTEN = 00): at the assertion of the end of Conversion (EOC) flag.
– In all other cases: after the execution of the ADSTP command, at the same time as the ADSTP bit is
cleared by hardware.
0: No ADC conversion is ongoing.
1: Write 1 to start the ADC. Read 1 means that the ADC is operating and may be converting.
Note: The software is allowed to set ADSTART only when ADEN
=
1 and ADDIS
=
0 (ADC is enabled
and there is no pending request to disable the ADC).
After writing to ADC_CHSELR register or changing CHSELRMOD or SCANDIRW, it is
mandatory to wait until CCRDY flag is asserted before setting ADSTART, otherwise, the value
written to ADSTART is ignored.
Bit 1
ADDIS
: ADC disable command
This bit is set by software to disable the ADC (ADDIS command) and put it into power-down state
(OFF state).
It is cleared by hardware once the ADC is effectively disabled (ADEN is also cleared by hardware at
this time).
0: No ADDIS command ongoing
1: Write 1 to disable the ADC. Read 1 means that an ADDIS command is in progress.
Note: Setting ADDIS to ‘1’ is only effective when ADEN
=
1 and ADSTART
=
0 (which ensures that no
conversion is ongoing)
Bit 0
ADEN
: ADC enable command
This bit is set by software to enable the ADC. The ADC is effectively ready to operate once the
ADRDY flag has been set.
It is cleared by hardware when the ADC is disabled, after the execution of the ADDIS command.
0: ADC is disabled (OFF state)
1: Write 1 to enable the ADC.
Note: The software is allowed to set ADEN only when all bits of ADC_CR registers are 0 (ADCAL
=
0,
ADSTP
=
0, ADSTART
=
0, ADDIS
=
0 and ADEN
=
0)