查看STC8G1K08 -20pin芯片手册,关于ADC范例程序参考,有如下问题不明白:
问题1:没有明白为什么要使用P_SW2 |= 0x80和P_SW2 &= 0x7f;?
问题2:P2 = ADC_RES; //读取 ADC 结果,P2是引脚吗?ADC_RES数据传给P2,P2各个io口数据是怎么样的?
//测试工作频率为 11.0592MHz
#include "reg51.h"
#include "intrins.h"
sfr ADC_CONTR = 0xbc;
sfr ADC_RES = 0xbd;
sfr ADC_RESL = 0xbe;
sfr ADCCFG = 0xde;
sfr P_SW2 = 0xba;
#define ADCTIM (*(unsigned char volatile xdata *)0xfea8)
sfr P0M1 = 0x93;
sfr P0M0 = 0x94;
sfr P1M1 = 0x91;
sfr P1M0 = 0x92;
sfr P2M1 = 0x95;
sfr P2M0 = 0x96;
sfr P3M1 = 0xb1;
sfr P3M0 = 0xb2;
sfr P4M1 = 0xb3;
sfr P4M0 = 0xb4;
sfr P5M1 = 0xc9;
sfr P5M0 = 0xca;
void main()
{
P0M0 = 0x00;
P0M1 = 0x00;
P1M0 = 0x00;
P1M1 = 0x00;
P2M0 = 0x00;
P2M1 = 0x00;
P3M0 = 0x00;
P3M1 = 0x00;
P4M0 = 0x00;
P4M1 = 0x00;
P5M0 = 0x00;
P5M1 = 0x00;
P1M0 = 0x00; //设置 P1.0 为 ADC 口
P1M1 = 0x01;
P_SW2 |= 0x80;
ADCTIM = 0x3f; //设置 ADC 内部时序
P_SW2 &= 0x7f;
ADCCFG = 0x0f; //设置 ADC 时钟为系统时钟/2/16
ADC_CONTR = 0x80; //使能 ADC 模块
while (1)
{
ADC_CONTR |= 0x40; //启动 AD 转换
![img](https://img-mid.csdnimg.cn/release/static/image/mid/ask/8cab7d6e1a8a4cd2ada3055007cdd0fa.png "#left")
_nop_();
_nop_();
while (!(ADC_CONTR & 0x20)); //查询 ADC 完成标志
ADC_CONTR &= ~0x20; //清完成标志
P2 = ADC_RES; //读取 ADC 结果
}
}