AT89C51RD2 Atmel Corporation, AT89C51RD2 Datasheet - Page 41

• Manufacturer Part Number: AT89C51RD2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RD2

• Flash (kbytes): 64 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Spi: 1
• Uart: 1
• Sram (kbytes): 2
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART
• Watchdog: Yes

4235K–8051–05/08
Table 13-4.
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 13-5 & Table 13-6).
Table 13-5.
CCAP0H - PCA Module 0 Compare/Capture Control Register High (0FAh)
CCAP1H - PCA Module 1 Compare/Capture Control Register High (0FBh)
CCAP2H - PCA Module 2 Compare/Capture Control Register High (0FCh)
CCAP3H - PCA Module 3 Compare/Capture Control Register High (0FDh)
CCAP4H - PCA Module 4 Compare/Capture Control Register High (0FEh)
Reset Value = 0000 0000b
Not bit addressable
ECOMn
Number
0
X
X
X
1
1
1
1
7 - 0
Bit
7
-
CAPPn
0
1
0
1
0
0
0
0
Mnemonic
PCA Module Modes (CCAPMn Registers)
CCAPnH Registers (n = 0 - 4)
Bit
6
-
-
CAPNn
0
0
1
1
0
0
0
0
Description
PCA Module n Compare/Capture Control
CCAPnH Value
MATn
5
-
0
0
0
0
1
1
0
1
TOGn
X
0
0
0
0
0
1
0
4
-
PWMm
0
0
0
0
0
0
1
0
3
-
ECCFn
X
X
X
X
X
X
0
0
AT89C51RD2/ED2
Module Function
16-bit capture by a positive-edge
trigger on CEXn
16-bit capture by a negative trigger on
CEXn
16-bit capture by a transition on CEXn
16-bit Software Timer/Compare mode.
16-bit High Speed Output
8-bit PWM
Watchdog Timer (module 4 only)
No Operation
2
-
1
-
0
-
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