RM0090 Rev 18 411/1749
RM0090 Analog-to-digital converter (ADC)
432
ADC with the shortest sequence may restart while the ADC with the longest sequence is
completing the previous conversions.
13.9.6 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. Figure 61 shows the behavior of an alternate trigger
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.
Figure 61. Alternate + regular simultaneous
If a trigger occurs during an injected conversion that has interrupted a regular conversion, it
is ignored. Figure 62 shows the behavior in this case (2nd trigger is ignored).
ADC1 reg
CH0 CH1 CH2
CH0
CH2 CH3
CH0
ADC1 inj
ADC2 reg
ADC2 inj
1st trigger
2nd trigger
synchro not lost
CH3 CH5 CH6 CH6 CH7
CH3 CH4
CH7 CH8
ai16062
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