ST STM32F301 6 Series Reference Manual page 210

Analog-to-digital converters (ADC)
12.3.18 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.
Table 32
and the trigger polarity.
EXTEN[1:0]
00
01
10
11
Note: The polarity of the regular trigger cannot be changed on-the-fly.
Table 33. Configuring the trigger polarity for injected external triggers
JEXTEN[1:0]
00
01
10
11
Note: The polarity of the injected trigger can be anticipated and changed on-the-fly. Refer to
Section 12.3.21: Queue of context for injected
The EXTSEL[3:0] and JEXTSEL[3:0] control bits select which out of 16 possible events can
trigger conversion for the regular and injected groups.
A regular group conversion can be interrupted by an injected trigger.
Note: The regular trigger selection cannot be changed on-the-fly.
The injected trigger selection can be anticipated and changed on-the-fly. Refer to
Section 12.3.21: Queue of context for injected conversions on page 215
Each ADC master shares the same input triggers with its ADC slave as described in
Figure 34.
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provides the correspondence between the EXTEN[1:0] and JEXTEN[1:0] values
Table 32. Configuring the trigger polarity for regular external triggers
Hardware Trigger detection disabled, software trigger detection enabled
Hardware Trigger with detection on the rising edge
Hardware Trigger with detection on the falling edge
Hardware Trigger with detection on both the rising and falling edges
Hardware Trigger with detection on the rising edge
Hardware Trigger with detection on the rising edge
Hardware Trigger with detection on the falling edge
Hardware Trigger with detection on both the rising and falling edges
Source
Source
conversions.
RM0366 Rev 5
RM0366