Rev. 1.6
201
C8051F310/1/2/3/4/5/6/7
18.2. Capture/Compare Modules
Each module can be configured to operate independently in one of six operation modes: Edge-triggered
Capture, Software Timer, High Speed Output, Frequency Output, 8-Bit Pulse Width Modulator, or 16-Bit
Pulse Width Modulator. Each module has Special Function Registers (SFRs) associated with it in the CIP-
51 system controller. These registers are used to exchange data with a module and configure the module's
mode of operation.
Table 18.2 summarizes the bit settings in the PCA0CPMn registers used to select the PCA capture/com-
pare module’s operating modes. Setting the ECCFn bit in a PCA0CPMn register enables the module's
CCFn interrupt. Note: PCA0 interrupts must be globally enabled before individual CCFn interrupts are rec-
ognized. PCA0 interrupts are globally enabled by setting the EA bit and the EPCA0 bit to logic 1. See
Figure 18.3 for details on the PCA interrupt configuration.
Figure 18.3. PCA Interrupt Block Diagram
Table 18.2. PCA0CPM Register Settings for PCA Capture/Compare Modules
PWM16
ECOM
CAPP CAPN
MAT
TOG
PWM
ECCF
Operation Mode
X
X
10000
X
Capture triggered by positive edge
on CEXn
X
X
01000
X
Capture triggered by negative edge
on CEXn
X
X
11000
X
Capture triggered by transition on
CEXn
X
1
00100
X
Software Timer
X
1
00110
X
High Speed Output
X
1
0
0
X
1
1
X
Frequency Output
0
1
0
0
X
0
1
X
8-Bit Pulse Width Modulator
1
1
0
0
X
0
1
X
16-Bit Pulse Width Modulator
X = Don’t Care
PCA0CN
C
F
C
R
C
C
F
0
C
C
F
2
C
C
F
1
C
C
F
4
C
C
F
3
PCA0MD
C
I
D
L
W
D
T
E
E
C
F
C
P
S
1
C
P
S
0
W
D
L
C
K
C
P
S
2
0
1
PCA Module 0
(CCF0)
PCA Module 1
(CCF1)
ECCF1
0
1
ECCF0
0
1
PCA Module 2
(CCF2)
ECCF2
0
1
PCA Module 3
(CCF3)
ECCF3
0
1
PCA Module 4
(CCF4)
ECCF4
PCA Counter/
Timer Overflow
0
1
Interrupt
Priority
Decoder
EPCA0
0
1
EA
0
1
PCA0CPMn
(for n = 0 to 4)
P
W
M
1
6
n
E
C
O
M
n
E
C
C
F
n
T
O
G
n
P
W
M
n
C
A
P
P
n
C
A
P
N
n
M
A
T
n
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