AT89C51ED2-SMRUM Datasheet, PDF (38/137 Pages) ATMEL Corporation – 8-bit Flash Microcontroller

Table 13-2. CCON Register
CCON - PCA Counter Control Register (D8h)
7
6
CF
CR
5
4
-
CCF4
3
CCF3
2
CCF2
1
CCF1
0
CCF0
Bit
Number
7
6
5
4
3
2
1
0
Bit
Mnemonic Description
PCA Counter Overflow flag
CF
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
CR
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.
CCF4
PCA Module 4 interrupt flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
CCF3
PCA Module 3 interrupt flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
CCF2
PCA Module 2 interrupt flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
CCF1
PCA Module 1 interrupt flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
CCF0
PCA Module 0 interrupt flag
Must be cleared by software.
Set by hardware when a match or capture occurs.
Reset Value = 00X0 0000b
Bit addressable
The watchdog timer function is implemented in Module 4 (See Figure 13-4).
The PCA interrupt system is shown in Figure 13-2.
38 AT89C51RD2/ED2
4235K–8051–05/08