Combined Regular Simultaneous + Alternate Trigger Mode; Figure 45. Alternate + Regular Simultaneous - ST STM32F205 series Reference Manual

RM0033
ADC with the shortest sequence may restart while the ADC with the longest sequence is
completing the previous conversions.
10.9.6

Combined regular simultaneous + alternate trigger mode

It is possible to interrupt the simultaneous conversion of a regular group to start the alternate
trigger conversion of an injected group.
interrupting a simultaneous regular conversion.
The injected alternate conversion is immediately started after the injected event. If regular
conversion is already running, in order to ensure synchronization after the injected
conversion, the regular conversion of all (master/slave) ADCs is stopped and resumed
synchronously at the end of the injected conversion.
Note: In combined regular simultaneous + alternate trigger mode, one must convert sequences
with the same length or ensure that the interval between triggers is longer than the long
conversion time of the 2 sequences (Dual ADC mode) /3 sequences (Triple ADC mode).
Otherwise, the ADC with the shortest sequence may restart while the ADC with the longest
sequence is completing the previous conversions.
If the conversion sequence is interrupted (for instance when DMA end of transfer occurs),
the multi-ADC sequencer must be reset by configuring it in independent mode first (bits
DUAL[4:0] = 00000) before reprogramming the interleaved mode.
CH0
ADC1 reg
ADC1 inj
CH3
ADC2 reg
ADC2 inj
If a trigger occurs during an injected conversion that has interrupted a regular conversion, it
is ignored.

Figure 45. Alternate + regular simultaneous

1st trigger
CH1 CH2
CH0
CH5 CH6
Figure 46 shows the behavior in this case (2nd trigger is ignored).
Figure 45 shows the behavior of an alternate trigger
CH2 CH3
CH6 CH7
2nd trigger
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Analog-to-digital converter (ADC)
CH3
CH7
CH0
synchro not lost
CH4
CH8
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