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GD32F403xx User Manual
204
2. Two channels sampled by two ADCs at the same time should be configured with the same
sampling time.
Figure 12-12. Routine parallel mode on 10 channels
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7
ADC0
ADC1
Routine
trigger
CH8
CH12
Sample
Convert
· · ·
· · ·
CH9
CH13
CH0
CH4
· · ·
· · ·
CH1
CH5
EOC
12.5.3.
Routine follow-up fast mode
The routine f ollow-up fast mode is applicable to sample the same channel of two ADCs. The
source of external trigger comes from the ADC0 routine channel (selected by the ETSRC[2:0]
bits in the ADC_CTL1 register). When the trigger occurs, ADC1 runs immediately and ADC0
runs af ter 7 ADC clock cycles.
If the continuous mode is enabled for both ADC0 and ADC1, the selected routine channels of
two ADCs are continuously converted. The behavior of f ollow-up fast mode shows in the
Figure 12-13. Routine follow-up fast mode (the CTN bit of ADCs are set).
Af ter an EOC interrupt is generated by ADC0 in case of setting the EOCIE bit, we can use a
32-bit DMA, which transf ers to SRAM the ADC_RDATA register containing the ADC1
converted data in the [31: 16] bits field and the ADC0 converted data in the [15: 0] bits field.
Note:
The sampling time of the routine channel of the two ADCs should be less than 7 ADC
clock cycles.
Figure 12-13. Routine follow-up fast mode (the CTN bit of ADCs are set)
CH1
ADC0
ADC1
Routine
trigger
Sample
Convert
· · ·
· · ·
EOC(ADC1 )
EOC(ADC0)
CH1
CH1
CH1
CH1
CH1
CH1
CH1
7 CK_ADC cycles
12.5.4.
Routine follow-up slow mode
The routine f ollow-up slow mode is applicable to sample the same channel of two ADCs. The
source of external trigger comes from the ADC0 routine channel (selected by the ETSRC[2:0]
bits in the ADC_CTL1 register).
When the trigger occurs, ADC1 runs immediately, ADC0 runs
after 14 ADC clock cycles, after the second 14 ADC clock cycles the ADC1 runs again.