测试了一下,用IO口输出方波,用示波器测最大只能是3.9M,大家帮看看是不是程序有问题,谢谢了,晶振用的是 11.0592M 的,板子就是ZLG的EasyARM 2131<br /><br /><br /><br />#include "config.h"<br /><br /><br />#define BO_OUT (1<<5) //P0.5脚输出<br /><br /><br /> int main (void)<br />{// add user source code <br /> PLLCON = 1; //设置PLL<br /> PLLCFG = 0x25; //M=5,P=2(试过M=4,P=2,更慢)<br /> PLLFEED = 0xAA;<br /> PLLFEED = 0x55;<br /> while((PLLSTAT & (1<<10))==0);<br /> PLLCON = 3;<br /> PLLFEED = 0xAA;<br /> PLLFEED = 0x55;<br /> VPBDIV = (VPBDIV&0xfc)|0x01; //VPB分频,设为和处理器时钟相同<br /><br /> PINSEL0 = PINSEL0&(~(0x03<<2)); <br /> IO0DIR = IO0DIR|BO_OUT; //设置IO脚方向,输出<br /> IO1DIR = IO1DIR|(0x03<<19); //点亮两个LED,指示用<br /> IO1CLR = 0x03<<19;<br /> while(1)<br /> {<br /> IO0SET = BO_OUT; //交替清零和置一,产生方波<br /> IO0CLR = BO_OUT;<br /> }<br /> return 0;<br />} |
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