ST STM32F301 6 Series Reference Manual page 213

RM0366
Note: When using triggered injection, one must ensure that the interval between trigger events is
longer than the injection sequence. For instance, if the sequence length is 28 ADC clock
cycles (that is two conversions with a sampling time of 1.5 clock periods), the minimum
interval between triggers must be 29 ADC clock cycles.
Auto-injection mode
If the JAUTO bit in the ADCx_CFGR register is set, then the channels in the injected group
are automatically converted after the regular group of channels. This can be used to convert
a sequence of up to 20 conversions programmed in the ADCx_SQR and ADCx_JSQR
registers.
In this mode, the ADSTART bit in the ADCx_CR register must be set to start regular
conversions, followed by injected conversions (JADSTART must be kept cleared). Setting
the ADSTP bit aborts both regular and injected conversions (JADSTP bit must not be used).
In this mode, external trigger on injected channels must be disabled.
If the CONT bit is also set in addition to the JAUTO bit, regular channels followed by injected
channels are continuously converted.
Note: It is not possible to use both the auto-injected and discontinuous modes simultaneously.
When the DMA is used for exporting regular sequencer's data in JAUTO mode, it is
necessary to program it in circular mode (CIRC bit set in DMA_CCRx register). If the CIRC
bit is reset (single-shot mode), the JAUTO sequence will be stopped upon DMA Transfer
Complete event.
Injection event
Reset ADC
1. The maximum latency value can be found in the electrical characteristics of the STM32F3xx datasheets.
Figure 35. Injected conversion latency
ADCCLK
max. latency
SOC
(1)
RM0366 Rev 5
Analog-to-digital converters (ADC)
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