Figure 32. PCA Timer/Counter
To PCA
modules
FPca/6
FPca/2
T0 OVF
P1.2
overflow
It
CH
CL
16-bit up counter
CMOD
0xD9
CIDL
CF
CPS1 CPS0 ECF
Idle
CCON
0xD8
CR
CCF1 CCF0
The CMOD register includes three additional bits associated with the PCA.
•
•
The CIDL bit which allows the PCA to stop during idle mode.
The ECF bit which when set causes an interrupt and the PCA overflow flag CF in
CCON register to be set when the PCA timer overflows.
The CCON register contains the run control bit for the PCA and the flags for the PCA
timer and each module.
•
•
The CR bit must be set to run the PCA. The PCA is shut off by clearing this bit.
The CF bit is set when the PCA counter overflows and an interrupt will be generated
if the ECF bit in CMOD register is set. The CF bit can only be cleared by software.
•
The CCF0:1 bits are the flags for the modules (CCF0 for module0...) and are set by
hardware when either a match or a capture occurs. These flags also can be cleared
by software.
72
AT89C5115
4128F–8051–05/06
ATMEL [ ATMEL ]
