DocID025202 Rev 7
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RM0365
Analog-to-digital converters (ADC)
392
Figure 60. Stopping ongoing regular and injected conversions
15.3.18 Conversion on external trigger and trigger polarity (EXTSEL, EXTEN,
JEXTSEL, JEXTEN)
A conversion or a sequence of conversions can be triggered either by software or by an
external event (e.g. timer capture, input pins). If the EXTEN[1:0] control bits (for a regular
conversion) or JEXTEN[1:0] bits (for an injected conversion) are different from 0b00, then
external events are able to trigger a conversion with the selected polarity.
The regular trigger selection is effective once software has set bit ADSTART=1 and the
injected trigger selection is effective once software has set bit JADSTART=1.
Any hardware triggers which occur while a conversion is ongoing are ignored.
•
If bit ADSTART=0, any regular hardware triggers which occur are ignored.
•
If bit JADSTART=0, any injected hardware triggers which occur are ignored.
provides the correspondence between the EXTEN[1:0] and JEXTEN[1:0] values
and the trigger polarity.
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Table 85. Configuring the trigger polarity for regular external triggers
EXTEN[1:0]
Source
00
Hardware Trigger detection disabled, software trigger detection enabled
01
Hardware Trigger with detection on the rising edge
10
Hardware Trigger with detection on the falling edge
11
Hardware Trigger with detection on both the rising and falling edges