使用PCF8591对C8051F进行AD转换电路原理图

/*01010101010101010101010101010101010101010101010101010101010101010101
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实验内容：
利用PCF8591进行AD数据转换，转换的值返回到P2口中，P2口与LED相连，观测LED灯是否正确显示
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硬件连接：
将P2口与8位LED指示灯相连。
在PCF8591的AIN0端口接入一个10K的电位器
DVK501(PCF8591PrlPort)    F320 EX
                           VCC    ---------   VCC
                           GND   ---------   GND
                           SDA    ---------   P1.0  
                           SCL    ---------   P1.1
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注意事项：
（1）若有加载库程序，请将光盘根目录下的“library”下的“C8051F”文件夹拷到D盘
（2）请详细阅读：光盘根目录下的“说明书首页.htm”里的相应产品说明
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10101010101010101010101010101010101010101010101010101010101010101010*/

#define _DVK501_F320_EX_

#include <c8051f320.h>
#include <../../../../library/C8051F/ws_clock.h>
#include <../../../../library/C8051F/ws_delay.h>
#include <../../../../library/C8051F/ws_iic_port.h>
#include <../../../../library/C8051F/ws_pcf8591.h>

void main(void)
{
uchar *pGetDat,tmp = 0;

PCA0MD &= ~0x40; // Clear watchdog timer enable
clock_external(); // Set oscillator in external,the clock is 12M
delay_ms(100);
Check_SDA();
XBR1 = 0x40; // Enable crossbar and weak pull-ups
SMBus_Init();
Enb_Interrupt();

while(1)
{
PCF8591_getAD(MODE0,CHNL0,pGetDat);
if(*pGetDat != tmp)
{
showLine(11,1,lcd_buffer,"0x%x2",*pGetDat);
refreshLCD(lcd_buffer);
tmp = *pGetDat;
P2 = tmp;
}
delay_ms(100);
}
}

#define MODE0 0x00 //Channel0 = AIN0;
//Channel1 = AIN1;
//Channel2 = AIN2;
//Channel3 = AIN3;
#define MODE1 0x10 //Channel0 = AIN3-AIN0;
//Channel1 = AIN3-AIN1
//Channel2 = AIN3-AIN2;
#define MODE2 0x20 //Channel0 = AIN0;
//Channel1 = AIN1;
//Channel2 = AIN3-AIN2;
#define MODE3 0x30 //Channel0 = AIN1-AIN0;
//Channel1 = AIN3-AIN2;
#define CHNL0 0 //Using Channel0
#define CHNL1 1 //Using Channel1
#define CHNL2 2 //Using Channel2
#define CHNL3 3 //Using Channel3

#define DAouputEn 0x40 //0x50 or 0x60 or 0x70 is also ok!

void PCF8591_getAD(uchar mode,uchar chan,uchar *ADC)
{
SMBus_Write(0x90,mode|chan,0,1);
SMBus_Read(0x91,ADC,1);
}

void PCF8591_setDA(uchar val)
{
SMBus_Write(0x90,DAouputEn,val,2);
}

调电位器上的旋钮，观察每次调完后LED灯的现象。