STC8系列单片机官网PWM程序为何测出的转换电压不对啊

ID:394367 · 发表于 2019-4-22 18:57

官网的这个程序是PWM输出DAC电压的么？我直接下载来测试怎么电压不对的，外部电路我用了2级RC电路（按以前stc官网给的参考电路）。以下就是官网的程序，求个帮忙，谢谢
#include "reg51.h"
#include "intrins.h"

//测试工作频率为11.0592MHz

sfr    CCON       = 0xd8;
sbit CF       = CCON^7;
sbit CR       = CCON^6;
sbit CCF3       = CCON^3;
sbit CCF2       = CCON^2;
sbit CCF1       = CCON^1;
sbit CCF0       = CCON^0;
sfr    CMOD       = 0xd9;
sfr    CL       = 0xe9;
sfr    CH       = 0xf9;
sfr    CCAPM0    = 0xda;
sfr    CCAP0L    = 0xea;
sfr    CCAP0H    = 0xfa;
sfr    PCA_PWM0 = 0xf2;
sfr    CCAPM1    = 0xdb;
sfr    CCAP1L    = 0xeb;
sfr    CCAP1H    = 0xfb;
sfr    PCA_PWM1 = 0xf3;
sfr    CCAPM2    = 0xdc;
sfr    CCAP2L    = 0xec;
sfr    CCAP2H    = 0xfc;
sfr    PCA_PWM2 = 0xf4;
sfr    CCAPM3    = 0xdd;
sfr    CCAP3L    = 0xed;
sfr    CCAP3H    = 0xfd;
sfr    PCA_PWM3 = 0xf5;

void main()
{
CCON = 0x00;
CMOD = 0x08;                               //PCA时钟为系统时钟
CL = 0x00;
CH = 0x00;
CCAPM0 = 0x42;                            //PCA模块0为PWM工作模式
PCA_PWM0 = 0x80;                         //PCA模块0输出6位PWM
CCAP0L = 0x20;                            //PWM占空比为50%[(40H-20H)/40H]
CCAP0H = 0x20;
CCAPM1 = 0x42;                            //PCA模块1为PWM工作模式
PCA_PWM1 = 0x40;                         //PCA模块1输出7位PWM
CCAP1L = 0x20;                            //PWM占空比为75%[(80H-20H)/80H]
CCAP1H = 0x20;
CCAPM2 = 0x42;                            //PCA模块2为PWM工作模式
PCA_PWM2 = 0x00;                         //PCA模块2输出8位PWM
CCAP2L = 0x20;                            //PWM占空比为87.5%[(100H-20H)/100H]
CCAP2H = 0x20;
CCAPM3 = 0x42;                            //PCA模块3为PWM工作模式
PCA_PWM3 = 0xc0;                         //PCA模块3输出10位PWM
CCAP3L = 0x20;                            //PWM占空比为96.875%[(400H-20H)/400H]
CCAP3H = 0x20;
CR = 1;                                  //启动PCA计时器

while (1);
}