RM0090: Reference manual - STMicroelectronics

RM0090 Analog-to-digital converter (ADC)
11.6 Conversion on external trigger and trigger polarity
Conversion can be triggered by an external event (e.g. timer capture, EXTI line). 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. Table 48 provides the correspondence between the EXTEN[1:0]
and JEXTEN[1:0] values and the trigger polarity.
Table 48. Configuring the trigger polarity
Source EXTEN[1:0] / JEXTEN[1:0]
Trigger detection disabled 00
Detection on the rising edge 01
Detection on the falling edge 10
Detection on both the rising and falling edges 11
Note: The polarity of the external trigger can be changed on the fly.
The EXTSEL[3:0] and JEXTSEL[3:0] control bits are used to select which out of 16 possible
events can trigger conversion for the regular and injected groups.
Table 49 gives the possible external trigger for regular conversion.
Table 49. External trigger for regular channels
TIM1_CH1 event
Source Type EXTSEL[3:0]
0000
TIM1_CH2 event 0001
TIM1_CH3 event 0010
TIM2_CH2 event 0011
TIM2_CH3 event 0100
TIM2_CH4 event 0101
TIM2_TRGO event 0110
TIM3_CH1 event
Internal signal from on-chip
timers
0111
TIM3_TRGO event 1000
TIM4_CH4 event 1001
TIM5_CH1 event 1010
TIM5_CH2 event 1011
TIM5_CH3 event 1100
TIM8_CH1 event 1101
TIM8_TRGO event 1110
EXTI line11 External pin 1111
Table 50 gives the possible external trigger for injected conversion.
Doc ID 018909 Rev 3 272/1416