RM0366 Datasheet, PDF (228/868 Pages) STMicroelectronics – This reference manual targets application developers

RM0366
Analog-to-digital converters (ADC)
Note:
Note:
This is a way to automatically adapt the speed of the ADC to the speed of the system which
will read the data.
The delay is inserted after each regular conversion (whatever DISCEN=0 or 1) and after
each sequence of injected conversions (whatever JDISCEN=0 or 1).
There is no delay inserted between each conversions of the injected sequence, except after
the last one.
During a conversion, a hardware trigger event (for the same group of conversions) occurring
during this delay is ignored.
This is not true for software triggers where it remains possible during this delay to set the
bits ADSTART or JADSTART to re-start a conversion: it is up to the software to read the
data before launching a new conversion.
No delay is inserted between conversions of different groups (a regular conversion followed
by an injected conversion or conversely):
• If an injected trigger occurs during the automatic delay of a regular conversion, the
injected conversion starts immediately (see Figure 59).
• Once the injected sequence is complete, the ADC waits for the delay (if not ended) of
the previous regular conversion before launching a new regular conversion (see
Figure 61).
The behavior is slightly different in auto-injected mode (JAUTO=1) where a new regular
conversion can start only when the automatic delay of the previous injected sequence of
conversion has ended (when JEOS has been cleared). This is to ensure that the software
can read all the data of a given sequence before starting a new sequence (see Figure 62).
To stop a conversion in continuous auto-injection mode combined with autodelay mode
(JAUTO=1, CONT=1 and AUTDLY=1), follow the following procedure:
1. Wait until JEOS=1 (no more conversions are restarted)
2. Clear JEOS,
3. Set ADSTP=1
4. Read the regular data.
If this procedure is not respected, a new regular sequence can re-start if JEOS is cleared
after ADSTP has been set.
In AUTDLY mode, a hardware regular trigger event is ignored if it occurs during an already
ongoing regular sequence or during the delay that follows the last regular conversion of the
sequence. It is however considered pending if it occurs after this delay, even if it occurs
during an injected sequence of the delay that follows it. The conversion then starts at the
end of the delay of the injected sequence.
In AUTDLY mode, a hardware injected trigger event is ignored if it occurs during an already
ongoing injected sequence or during the delay that follows the last injected conversion of
the sequence.
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