"( very confused after reading Intel PCA Cook Book )."

You mean these 7 lines ?

INIT-PWM:
MOV CMOD, #02H ; Clock input 4 250 nsec at 16 MHz
MOV CL, #00H ; Frequency of output 4 15.6 KHz
MOV CH, #00H
MOV CCAPM0, #42H ; Module 0 in PWM mode
MOV CCAP0L, #00H
MOV CCAP0H, #128D ; 50 percent duty cycle
SETB CR ; Turn on PCA timer

Maybe you will have to give it another go....

Or tell what is it that confused you.

Raghu