Rev. 1.2
163
C8051T600/1/2/3/4/5/6
26.3. 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 sys-
tem controller. These registers are used to exchange data with a module and configure the module's mode
of operation.
Table 26.2 summarizes the bit settings in the PCA0CPMn register used to select the PCA
capture/compare module’s operating mode. Setting the ECCFn bit in a PCA0CPMn register enables the
module's CCFn interrupt.
Table 26.2. PCA0CPM Bit Settings for PCA Capture/Compare Modules
Operational Mode
PCA0CPMn
Bit Number 76543210
Capture triggered by positive edge on CEXn
X X 10000 A
Capture triggered by negative edge on CEXn
X X 01000 A
Capture triggered by any transition on CEXn
X X 11000 A
Software Timer
X B 00100 A
High Speed Output
X B 00110 A
Frequency Output
X B 00011 A
8-Bit Pulse Width Modulator
0 B 0 0 C 0 1 A
16-Bit Pulse Width Modulator
1 B 0 0 C 0 1 A
Notes:
1.
X = Don’t Care (no functional difference for individual module if 1 or 0).
2.
A = Enable interrupts for this module (PCA interrupt triggered on CCFn set to 1).
3.
B = When set to 0, the digital comparator is off. For high speed and frequency output modes, the associated
pin will not toggle. In any of the PWM modes, this generates a 0% duty cycle (output = 0).
4.
C = When set, a match event will cause the CCFn flag for the associated channel to be set.
