Conversion On External Trigger And Trigger Polarity (Extsel, Exten); Table 32. Configuring The Trigger Polarity; Figure 26. Stopping An Ongoing Conversion - STMicroelectronics STM32F05 series Reference Manual

Analog-to-digital converter (ADC)

Figure 26. Stopping an ongoing conversion

ADC State
ADSTART
12.5 Conversion on external trigger and trigger polarity
EXTEN)
A conversion or a sequence of conversion can be triggered either by software or by an
external event (for example timer capture). If the EXTEN[1:0] control bits are not equal to
"0b00", then external events are able to trigger a conversion with the selected polarity. The
trigger selection is effective once software has set bit ADSTART=1.
Any hardware triggers which occur while a conversion is ongoing are ignored.
If bit ADSTART=0, any hardware triggers which occur are ignored.
Table 32
polarity.
Table 32.
Trigger detection disabled
Detection on rising edge
Detection on falling edge
Detection on both rising and falling edges
Note: The polarity of the external trigger cannot be changed on the fly.
The EXTSEL[2:0] control bits are used to select which of 8 possible events can trigger
conversions.
Table 33
Software source trigger events can be generated by setting the ADSTART bit in the
ADC_CR register.
Table 33.
Name
TRG0
TRG1
178/742
RDY
set
by SW
ADSTOP
ADC_DR
provides the correspondence between the EXTEN[1:0] values and the trigger
Configuring the trigger polarity
Source
gives the possible external trigger for regular conversion.
External triggers
TIM1_TRGO
TIM1_CC4
Doc ID 018940 Rev 1
SAMPLING CH(N) CONVERTING CH(N)
DATA N-1
Source
RDY
cleared
by HW
set
cleared
by HW
by SW
(EXTSEL,
EXTEN[1:0]
00
01
10
11
EXTSEL[2:0]
000
001
RM0091