Discontinuous Mode; Figure 24. Injected Conversion Latency - ST STM32F102 Series Reference Manual

RM0008

Figure 24. Injected conversion latency

ADC clock
Inj. event
Reset ADC
SOC
1. The maximum latency value can be found in the electrical characteristics of the STM32F101xx and
STM32F103xx datasheets.
10.3.10

Discontinuous mode

Regular group
This mode is enabled by setting the DISCEN bit in the ADC_CR1 register. It can be used to
convert a short sequence of n conversions (n <=8) which is a part of the sequence of
conversions selected in the ADC_SQRx registers. The value of n is specified by writing to
the DISCNUM[2:0] bits in the ADC_CR1 register.
When an external trigger occurs, it starts the next n conversions selected in the ADC_SQRx
registers until all the conversions in the sequence are done. The total sequence length is
defined by the L[3:0] bits in the ADC_SQR1 register.
Example:
n = 3, channels to be converted = 0, 1, 2, 3, 6, 7, 9, 10
1st trigger: sequence converted 0, 1, 2
2nd trigger: sequence converted 3, 6, 7
3rd trigger: sequence converted 9, 10 and an EOC event generated
4th trigger: sequence converted 0, 1, 2
Note: When a regular group is converted in discontinuous mode, no rollover will occur.
When all sub groups are converted, the next trigger starts conversion of the first sub-group.
In the example above, the 4th trigger reconverts the 1st sub-group channels 0, 1 and 2.
Injected group
This mode is enabled by setting the JDISCEN bit in the ADC_CR1 register. It can be used to
convert the sequence selected in the ADC_JSQR register, channel by channel, after an
external trigger event.
When an external trigger occurs, it starts the next channel conversions selected in the
ADC_JSQR registers until all the conversions in the sequence are done. The total sequence
length is defined by the JL[1:0] bits in the ADC_JSQR register.
Analog-to-digital converter (ADC)
(1)
max latency
155/690