GD32VF103 User Manual
155
ADC_IN0
ADC_IN1
· ·
·
ADC_IN15
GPIO
C
h
a
n
n
e
l
s
e
le
c
to
r
V
SENSE
V
REFP
V
REFN
V
DDA
V
SSA
6~12bit
Injected data registers
(
16 bits x 4
)
Regular data registers
(
16 bits
)
Regular
channels
Inserted
channels
Channel Management
Trig select
E
X
T
I1
1
T
IM
E
R
0
_
C
H
0
T
IM
E
R
0
_
C
H
1
T
IM
E
R
0
_
C
H
2
T
IM
E
R
1
_
C
H
1
Trig select
E
X
T
I1
5
T
IM
E
R
0
_
T
R
G
O
T
IM
E
R
0
_
C
H
3
T
IM
E
R
1
_
T
R
G
O
T
IM
E
R
1
_
C
H
0
Analog
watchdog
A
P
B
B
U
S
EOC
EOIC
watchdog
event
Interrupt
generator
ADC
Interrupt
SAR ADC
CLB
self calibration
DRES[1:0]
12, 10, 8, 6 bits
OVSS[3:0]
OVSR[2:0]
OVSEN
TOVS
Over
sampler
…
…
V
REFINT
11.4.1.
Calibration (CLB)
The ADC has a foreground calibration feature. During the procedure, the ADC calculates a
calibration factor which is internally applied to the ADC until the next ADC power-off. The
application must not use the ADC during calibration and must wait until it is completed.
Calibration should be performed before starting A/D conversion. The calibration is initiated by
software by setting bit CLB=1. CLB bit stays at 1 during all the calibration sequence. It is then
cleared by hardware as soon as the calibration is completed.
When the ADC operating conditions change (such as supply power voltage V
DDA
, positive
reference voltage V
REF+
, temperature and so on), it is recommended to re-run a calibration
cycle.
The internal analog calibration can be reset by setting the RSTCLB bit in ADC_CTL1 register.
Calibration software procedure:
1.
Ensure that ADCON=1.
2.
Delay 14 ADCCLK to wait for ADC stability.
3.
Set RSTCLB (optional).
4.
Set CLB=1.
5.
Wait until CLB=0.