TS87C51RD2 ATMEL Corporation, TS87C51RD2 Datasheet - Page 29

• Manufacturer Part Number: TS87C51RD2
• Description: (TS8xC51Rx2) High Performance 8-bit Microcontroller
• Manufacturer: ATMEL Corporation

6.3.1
4188E–8051–08/06
PCA Capture Mode
There are two additional registers associated with each of the PCA modules. They are CCAPnH
and CCAPnL and these are the registers that store the 16-bit count when a capture occurs or a
compare should occur. When a module is used in the PWM mode these registers are used to
control the duty cycle of the output (See Table 6-8 & Table 6-9)
Table 6-8.
Table 6-9.
Table 6-10.
Table 6-11.
To use one of the PCA modules in the capture mode either one or both of the CCAPM bits
CAPN and CAPP for that module must be set. The external CEX input for the module (on port 1)
is sampled for a transition. When a valid transition occurs the PCA hardware loads the value of
the PCA counter registers (CH and CL) into the module's capture registers (CCAPnL and
CCAPnH). If the CCFn bit for the module in the CCON SFR and the ECCFn bit in the CCAPMn
SFR are set then an interrupt will be generated (Refer to Figure 6-6).
CCAPnH Address
CCAPnL Address
Address 0F9H
Address 0E9H
n = 0 - 4
n = 0 - 4
CH
CL
CCAPnH: PCA Modules Capture/Compare Registers High
CCAPnL: PCA Modules Capture/Compare Registers Low
CH: PCA Counter High
CL: PCA Counter Low
CCAP2L=0ECH
CCAP3L=0EDH
CCAP0L=0EAH
CCAP1L=0EBH
CCAP4L=0EEH
CCAP1H=0FBH
CCAP2H=0FCH
CCAP3H=0FDH
CCAP4H=0FEH
CCAP0H=0FAH
Reset value
Reset value
Reset value
Reset value
7
0
7
0
7
0
7
0
6
0
6
0
6
0
6
0
5
0
5
0
5
0
5
0
4
0
4
0
4
0
4
0
AT/TS8xC51Rx2
3
0
3
0
3
0
3
0
2
0
2
0
2
0
2
0
1
0
1
0
1
0
1
0
0
0
0
0
0
0
0
0
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