AT89C51RE2 Atmel Corporation, AT89C51RE2 Datasheet - Page 85

• Manufacturer Part Number: AT89C51RE2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RE2

• Flash (kbytes): 128 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Spi: 1
• Uart: 2
• Sram (kbytes): 8.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART/OCD
• Watchdog: Yes

7663E–8051–10/08
Table 55. CCON Register
CCON - PCA Counter Control Register (D8h)
Reset Value = 00X0 0000b
Not bit addressable
The watchdog timer function is implemented in module 4 (See Figure 33).
The PCA interrupt system is shown in Figure 31.
Number
Bit
CF
7
7
6
5
4
3
2
1
0
Mnemonic
CCF4
CCF3
CCF2
CCF1
CCF0
CR
Bit
CR
CF
6
-
Description
PCA Counter Overflow flag
Set by hardware when the counter rolls over. CF flags an interrupt if bit ECF in CMOD is
set. CF
may be set by either hardware or software but can only be cleared by software.
PCA Counter Run control bit
Must be cleared by software to turn the PCA counter off.
Set by software to turn the PCA counter on.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
PCA Module 4 interrupt flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
PCA Module 3 interrupt flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
PCA Module 2 interrupt flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
PCA Module 1 interrupt flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
PCA Module 0 interrupt flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
5
-
CCF4
4
CCF3
3
CCF2
2
AT89C51RE2
CCF1
1
CCF0
0
85