Analog-to-digital converters (ADC) RM0440
670/2126 RM0440 Rev 4
Injected simultaneous mode
This mode is selected by programming bits DUAL[4:0]=00101
This mode converts an injected group of channels. The external trigger source comes from
the injected group multiplexer of the master ADC (selected by the JEXTSEL bits
in the
ADC_JSQR register).
Note: Do not convert the same channel on the two ADCs (no overlapping sampling times for the
two ADCs when converting the same channel).
In simultaneous mode, one must convert sequences with the same length or ensure that the
interval between triggers is longer than the longer of the 2 sequences. Otherwise, the ADC
with the shortest sequence may restart while the ADC with the longest sequence is
completing the previous conversions.
Regular conversions can be performed on one or all ADCs. In that case, they are
independent of each other and are interrupted when an injected event occurs. They are
resumed at the end of the injected conversion group.
• At the end of injected sequence of conversion event (JEOS) on the master ADC, the
converted data is stored into the master ADC_JDRy registers and a JEOS interrupt is
generated (if enabled)
• At the end of injected sequence of conversion event (JEOS) on the slave ADC, the
converted data is stored into the slave ADC_JDRy registers and a JEOS interrupt is
generated (if enabled)
• If the duration of the master injected sequence is equal to the duration of the slave
injected one (like in Figure 138), it is possible for the software to enable only one of the
two JEOS interrupt (ex: master JEOS) and read both converted data (from master
ADC_JDRy and slave ADC_JDRy registers).
Figure 138. Injected simultaneous mode on 4 channels: dual ADC mode
If JDISCEN=1, each simultaneous conversion of the injected sequence requires an injected
trigger event to occur.
This mode can be combined with AUTDLY mode:
• Once a simultaneous injected sequence of conversions has ended, a new injected
trigger event is accepted only if both JEOS bits of the master and the slave ADC have
been cleared (delay phase). Any new injected trigger events occurring during the
ongoing injected sequence and the associated delay phase are ignored.
• Once a regular sequence of conversions of the master ADC has ended, a new regular
trigger event of the master ADC is accepted only if the master data register (ADC_DR)
has been read. Any new regular trigger events occurring for the master ADC during the
MASTER ADC
SLAVE ADC
End of injected sequence on
MASTER and SLAVE ADC
MS31900V1
Trigger
CH1
CH15 CH14 CH13 CH12
CH2 CH3 CH4
Sampling
Conversion
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