AT32F421
Series Reference Manual
2022.11.11
Page 307
Rev 2.02
Figure 18-1 ADC1 block diagram
PCLK2
ADCCLK
V
...
PCTEN
Preempted
conversion start
PCTESEL
Ordinary
conversion start
OCTESEL
OCTEN
EXINT11
TMR1_CH1
TMR1_CH2
TMR1_CH3
TMR3_TRGOUT
TMR15_CH1
OCSWTRG
TMR1_TRGOUT
TMR1_CH4
TMR3_CH4
TMR15_TRGOUT
PCSWTRG
Trigger
detection
ADC_IN1
ADC_IN0
ADC_IN14
INTRV
...
ADC prescaler
ADCDIV
Analog-to-
digital
converter
Channel
manegement
Preempted
channels
Ordinary
channels
Address/Data bus
Data
management
GPIO
CCE flag
PCCE flag
ADC
interrupt
to NVIC
DMA
request
VSSA
V DDA
Trigger
detection
VMOR flag
CCEIEN
PCCEIEN
VMORIEN
Voltage
monitor
Preempted data register
(4*16 bits)
Ordinary data register
(16 bits)
EXINT15
Temp.sensor
Input pin description:
V
DDA:
Analog supply, ADC analog supply
V
SSA:
Analog supply ground, ADC analog supply ground
ADCx_IN: Analog input signal channels
Refer to the data sheet for details on the input pins and voltage limits.
18.4 ADC functional overview
18.4.1 Channel management
Analog signal channel input:
There are 18 analog signal channel inputs for each of the ADCs, expressed by ADC_Inx (x=0 to 17).
ADC1_IN0 to ADC1_IN14 are referred to as the external analog input, ADC1_IN15 as Vss,
ADC1_IN15 as an internal temperature sensor, ADC1_IN17 as an internal reference voltage.
Channel conversion
The conversions are divided into two groups: ordinary and preempted channels. The preempted group
has priority over the ordinary group.
If the preempted channel trigger occurs during the ordinary channel conversion, then the ordinary