GD32F20x User Manual
264
Figure 14-12. Data alignment of 6-bit resolution
Sign
Sign
Sign
Sign
D5
D4
D3
D2
D1
D0
0
0
0
0
0
0
0
0
0
0
D5
D4
D3
D2
D1
D0
0
0
0
0
0
0
Regular group data
Inserted group data
Sign
D5
D4
0
D3
D2
D1
D0
0
0
0
0
0
0
0
0
D1
D0
0
0
0
0
D5
D4
D3
D2
0
0
0
0
0
0
Regular group data
Inserted group data
DAL=0
DAL=1
14.4.9.
Programmable sample time
The number of ADCCLK cycles which is used to sample the input voltage can be specified
by the SPTn[2:0] bits in the ADC_SAMPT0 and ADC_SAMPT1 registers. A different sample
time can be specified for each channel. For 12-bits resolution, the total conversion time is
“sampling time + 12.5” ADCCLK cycles.
Example:
ADCCLK = 14MHz and sample time is 1.5 cycles, the total conversion time is
“1.5+12.5”
ADCCLK cycles, that means 1us.
14.4.10.
External trigger
The conversion of regular or inserted group can be triggered by rising edge of external trigger
inputs. The external trigger source of regular channel group is controlled by the ETSRC[2:0]
bits in the ADC_CTL1 register, while the external trigger source of inserted channel group is
controlled by the ETSIC[2:0] bits in the ADC_CTL1 register
ETSRC[2:0] and ETSIC[2:0] control bits are used to specify which out of 8 possible events
can trigger conversion for the regular and inserted groups.
Table 14-3. External trigger for regular channels for ADC0 and ADC1
ETSRC [2:0]
Trigger Source
Trigger Type
000
TIMER0_CH0
Internal on-chip signal
001
TIMER0_CH1
010
TIMER0_CH2
011
TIMER1_CH1
100
TIMER2_TRGO
101
TIMER3_CH3
110
EXTI_11/TIMER7_TRGO
External signal
111
SWRCST
Software trigger
Summary of Contents for GD32F20 Series
Page 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Page 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Page 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Page 385: ...GD32F20x User Manual 385 ...
Page 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...