
C8051F52x/F53x
52
Rev. 1.4
4. 12-Bit ADC (ADC0)
The ADC0 on the C8051F52x/F52xA/F53x/F53xA Family consists of an analog multiplexer (AMUX0) with
16/6 total input selections, and a 200 ksps, 12-bit successive-approximation-register (SAR) ADC with inte-
grated track-and-hold, programmable window detector, programmable gain, and hardware accumulator.
The ADC0 subsystem has a special Burst Mode which can automatically enable ADC0, capture and accu-
mulate samples, then place ADC0 in a low power shutdown mode without CPU intervention. The AMUX0,
data conversion modes, and window detector are all configurable under software control via the Special
Function Registers shown in
Figure 4.1. ADC0 inputs are single-ended and may be configured to measure
P0.0-P1.7, the Temperature Sensor output, VDD, or GND with respect to GND. The voltage reference for
the AD0EN bit in the ADC0 Control register (ADC0CN) is set to logic 1, or when performing conversions in
Burst Mode. ADC0 is in low power shutdown when AD0EN is logic 0 and no Burst Mode conversions are
taking place.
Figure 4.1. ADC0 Functional Block Diagram
4.1. Analog Multiplexer
AMUX0 selects the input channel to the ADC. Any of the following may be selected as an input: P0.0–
P1.7, the on-chip temperature sensor, the core power supply (VDD), or ground (GND). ADC0 is single-
ended and all signals measured are with respect to GND. The ADC0 input channels are selected using
Important Note About ADC0 Input Configuration: Port pins selected as ADC0 inputs should be config-
ured as analog inputs, and should be skipped by the Digital Crossbar. To configure a Port pin for analog
input, set to 0 the corresponding bit in register PnMDIN (for n = 0,1). To force the Crossbar to skip a Port
page 120 for more Port I/O configuration details.
ADC0CN
AD
0CM
0
AD
0CM
1
AD0LJ
ST
AD
0
W
IN
T
AD
0
B
U
S
Y
AD
0
IN
T
B
URS
T
E
N
AD0
E
N
Start
Conversion
VDD
19-to-1
AMUX0
VDD
P0.0
P0.7*
P1.0*
P1.7*
ADC0MX
AD
C0M
X
4
AD
C0M
X
3
AD
C0M
X
2
AD
C0M
X
1
AD
C0M
X
0
GND
Temp Sensor
ADC0TK
AD0P
WR3
AD0P
WR2
AD0P
WR1
AD0P
WR0
AD
0TM
1
AD
0TM
0
AD0T
K1
AD0T
K0
Burst Mode
Logic
Start
Conversion
Burst Mode
Oscillator
25 MHz Max
SYSCLK
FC
L
K
*Available on ‘F53x/’F53xA
devices
00
AD0BUSY (W)
10
CNVSTR Input
Timer 2 Overflow
11
01
Timer 1 Overflow
12-Bit
SAR
ADC
RE
F
FCLK
AD
C0H
32
ADC0LTH
AD0WINT
ADC0LTL
ADC0GTH ADC0GTL
AD
C0
L
ADC0CF
GA
IN
EN
AD
0RPT
0
AD
0RPT
1
AD0SC
0
AD0SC
1
AD0SC
2
AD0SC
3
AD0SC
4
AD
0
P
OS
T
AD0PRE
AD
0T
M
1
:0
Accumulator
Window
Compare
Logic
Selectable
Gain
P0.6*
ADC0GNL
ADC0GNH
ADC0GNA