1.XTAL1 XTAL2 外接由兩個電容與晶振的并聯(lián)諧振時鐘電路

C1,C2 選30pF,晶振選1.2-12MHz,設(shè)計時,當使晶振各電容盡可能的與C51單片機靠近,以保證穩(wěn)定可靠

2.或用外部振蕩器接至XTAL2,XTAL1接地,注意:XTAL1如果不接地的話,Electrical Rule Check會給出錯誤如下下:

ELECTRICAL RULES CHECK REPORT
=============================
Design: D:proteus-designyx-designIO-1.DSN
Doc. no.:
Revision:
Author:
Created: 07/02/06
Modified: 07/02/06

UNDRIVEN: U1,XTAL1 (Input)

Netlist generated OK.
ERC errors found.