Manual

AT89C5131

4136A–USB–03/03

Table 55. PCA Module Modes (CCAPMn Registers)

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 56 and

Table 57)

ECOMn CAPPn CAPNn MATn TOGn

PWM

ECCF

n Module Function

0 0 0 0000 No Operation

X 1 0 000X

16-bit capture by a positive-

edge trigger on CEXn

X 0 1 000X

16-bit capture by a negative

trigger on CEXn

X 1 1 000X

16-bit capture by a transition on

CEXn

1 0 0 100X

16-bit Software Timer/Compare

mode.

1 0 0 1 1 0 X 16-bit High Speed Output

1 0 0 00108-bit PWM

10 01X0X

Watchdog Timer (module 4

only)