P89C51RB2BA datasheet(29/52 Pages) PHILIPS

부품명	P89C51RB2BA

상세설명	80C51 8-bit Flash microcontroller family 16KB/32KB/64KB ISP/IAP Flash with 512B/512B/1KB RAM

PDF	52 Pages

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제조업체	PHILIPS [NXP Semiconductors]

홈페이지	http://www.nxp.com

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29 / 52 page

Philips Semiconductors

Preliminary specification

89C51RB2/89C51RC2/

89C51RD2

80C51 8-bit Flash microcontroller family

16KB/32KB/64KB ISP/IAP Flash with 512B/512B/1KB RAM

1999 Sep 23

INIT_WATCHDOG:

MOV CCAPM4, #4CH

; Module 4 in compare mode

MOV CCAP4L, #0FFH

; Write to low byte first

MOV CCAP4H, #0FFH

; Before PCA timer counts up to

; FFFF Hex, these compare values

; must be changed

ORL CMOD, #40H

; Set the WDTE bit to enable the

; watchdog timer without changing

; the other bits in CMOD

;

;********************************************************************

;

; Main program goes here, but CALL WATCHDOG periodically.

;

;********************************************************************

;

WATCHDOG:

CLR EA

; Hold off interrupts

MOV CCAP4L, #00

; Next compare value is within

MOV CCAP4H, CH

; 255 counts of the current PCA

SETB EA

; timer value

RET

Figure 26. PCA Watchdog Timer Initialization Code

P89C51RB2BA 데이터시트(PDF) 29 Page - NXP Semiconductors