P87C51FB-4B,557 NXP Semiconductors, P87C51FB-4B,557 Datasheet - Page 32

• Manufacturer Part Number: P87C51FB-4B,557
• Manufacturer: NXP Semiconductors

Philips Semiconductors
(8XC51FX and 8XC51RX+ ONLY)
2000 Aug 07
80C51 8-bit microcontroller family
8K–64K/256–1K OTP/ROM/ROMless, low voltage (2.7V–5.5V),
low power, high speed (33MHz)
INIT_WATCHDOG:
;
;********************************************************************
;
; Main program goes here, but CALL WATCHDOG periodically.
;
;********************************************************************
;
WATCHDOG:
MOV CCAPM4, #4CH
MOV CCAP4L, #0FFH
MOV CCAP4H, #0FFH
ORL CMOD, #40H
CLR EA
MOV CCAP4L, #00
MOV CCAP4H, CH
SETB EA
RET
; Module 4 in compare mode
; Write to low byte first
; Before PCA timer counts up to
; FFFF Hex, these compare values
; must be changed
; Set the WDTE bit to enable the
; Hold off interrupts
; Next compare value is within
; 255 counts of the current PCA
; timer value
; watchdog timer without changing
; the other bits in CMOD
Figure 26. PCA Watchdog Timer Initialization Code
32
8XC51RA+/RB+/RC+/RD+/80C51RA+
8XC51FA/FB/FC/80C51FA
Product specification
8XC54/58