查看“树莓派系列教程：PCF8591 AD/DA”的源代码



树莓派本身没有AD/DA功能，如果树莓派外接模拟传感器，则必须外接AD/DA功能扩展板才能用。Pioneer 600扩展带有AD/DA芯片PCF8591,pcf8591带1通道8位DA,4通道8位AD,通过I2C控制。


<b><span style="font-size:9.0pt;font-family:
宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">一、</b><b>DAC

</b>


1<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">、bcm2835<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">程序
===  cpp代码 ===
<syntaxhighlight lang="python">
#include <bcm2835.h>  
#include <stdio.h>
#include <unistd.h>

int main(int argc, char **argv)  
{  
	char Buf[]={0,0};
	unsigned char value=0;

	if (!bcm2835_init())return 1;  
	bcm2835_i2c_begin(); 
	bcm2835_i2c_setSlaveAddress(0x48);  
    bcm2835_i2c_set_baudrate(10000);  
    printf("start..........\n"); 

    while(1)  
    {  
		Buf[0] = 0x40;
		Buf[1] = value++;
		bcm2835_i2c_write(Buf,2);
		printf("AOUT: %d\n",value);

        bcm2835_delay(20);  
	}  

    bcm2835_i2c_end();  
    bcm2835_close();  
    return 0;  
}</syntaxhighlight>
<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white"> 
<span style="font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;
mso-bidi-font-family:Tahoma;color:#555555;background:white">编译并执行
<syntaxhighlight lang="python">
gcc –Wall pcf8591.c –o pcf8591 –lbcm2835
sudo ./ pcf8591
</syntaxhighlight>
<span style="font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;
mso-bidi-font-family:Tahoma;color:#555555;background:white"> 
2、Python<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">程序
<syntaxhighlight lang="python">
#!/usr/bin/python
# -*- coding:utf-8 -*-
import smbus
import time

address = 0x48
cmd = 0x40
value = 0 

bus = smbus.SMBus(1)
while True:
    bus.write_byte_data(address,cmd,value)
    value += 1
    if value == 256:
        value =0
    print("AOUT:%3d" %value)
    time.sleep(0.01)
</syntaxhighlight>
<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white"> 
<span style="font-size:9.0pt;font-family:宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:
Tahoma;mso-bidi-font-family:Tahoma;color:#555555;background:white">执行程序
<syntaxhighlight lang="python">
sudo python pcf8591</syntaxhighlight>
<span style="font-size:9.0pt;font-family:宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:
Tahoma;mso-bidi-font-family:Tahoma;color:#555555;background:white"> 
3、wiringPi<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">程序
<syntaxhighlight lang="python">
#include <wiringpi.h>
#include <pcf8591.h>
#include <stdio.h>

#define Address 0x48
#define BASE 64
#define A0 BASE+0
#define A1 BASE+1
#define A2 BASE+2
#define A3 BASE+3

int main(void)
{
    unsigned char value;
    wiringPiSetup();
    pcf8591Setup(BASE,Address);

    while(1)
    {   
        analogWrite(A0,value);
        printf("AOUT: %d\n",value++);
        delay(20);
    }   
}
</syntaxhighlight>
<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">编译并执行程序
<syntaxhighlight lang="python">
gcc –Wall pcf8591.c –o pcf8591 –lbcm2835 -lwiringPi
sudo ./ pcf8591
</syntaxhighlight>
<span style="font-size:9.0pt;font-family:宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:
Tahoma;mso-bidi-font-family:Tahoma;color:#555555;background:white">二、ADC


<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">

1、bcm2835<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">程序
<syntaxhighlight lang="python">
#include <bcm2835.h>
#include <stdio.h>
#include <unistd.h>

int main(int argc, char **argv)  
{  
    char Buf[]={0};
    unsigned char i;

    if (!bcm2835_init())return 1;  
    bcm2835_i2c_begin(); 
    bcm2835_i2c_setSlaveAddress(0x48);  
    bcm2835_i2c_set_baudrate(10000);  
    printf("start..........\n"); 

    while(1)  
    {   
        for(i = 0;i < 4;i++)
        {   
            Buf[0] = i;  
            bcm2835_i2c_write_read_rs(Buf,1,Buf,1);  
            bcm2835_i2c_read (Buf,1);
            printf("AIN%d:%5.2f  ",i,(double)Buf[0]*3.3/255);
        }   
        printf("\n");
        bcm2835_delay(100);  
    }   
    
    bcm2835_i2c_end();  
    bcm2835_close();  
    return 0;  
}</syntaxhighlight>
<span style="font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;
mso-bidi-font-family:Tahoma;color:#555555;background:white">编译并执行
<syntaxhighlight lang="python">
gcc –Wall pcf8591.c –o pcf8591 –lbcm2835
sudo ./ pcf8591
</syntaxhighlight>
<span style="font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;
mso-bidi-font-family:Tahoma;color:#555555;background:white"> 
2<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">、Python<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">程序
<syntaxhighlight lang="python">
#!/usr/bin/python
# -*- coding:utf-8 -*-
import smbus
import time

address = 0x48
A0 = 0x40
A1 = 0x41
A2 = 0x42
A3 = 0x43
bus = smbus.SMBus(1)
while True:
    bus.write_byte(address,A0)  
    value = bus.read_byte(address)
    print("AOUT:%1.3f  " %(value*3.3/255))
    time.sleep(0.1)
</syntaxhighlight>
<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white"> 
<span style="font-size:9.0pt;font-family:宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:
Tahoma;mso-bidi-font-family:Tahoma;color:#555555;background:white">执行程序
<syntaxhighlight lang="python">
sudo python pcf8591</syntaxhighlight>
<span style="font-size:9.0pt;font-family:宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:
Tahoma;mso-bidi-font-family:Tahoma;color:#555555;background:white"> 
3、wiringPi<span style="font-size:9.0pt;font-family:宋体;
mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;mso-bidi-font-family:
Tahoma;color:#555555;background:white">程序
<syntaxhighlight lang="python">
#include <wiringpi.h>
#include <pcf8591.h>
#include <stdio.h>

#define Address 0x48
#define BASE 64
#define A0 BASE+0
#define A1 BASE+1
#define A2 BASE+2
#define A3 BASE+3

int main(void)
{
    int value;
    wiringPiSetup();
    pcf8591Setup(BASE,Address);

    while(1)
    {   
        value = analogRead(A0);
        printf("Analoge: %dmv\n",value*3300/255);
        delay(1000);
    }   
}</syntaxhighlight>
<span style="font-size:
9.0pt;font-family:宋体;mso-ascii-font-family:Tahoma;mso-hansi-font-family:Tahoma;
mso-bidi-font-family:Tahoma;color:#555555;background:white">编译并执行程序
<syntaxhighlight lang="python">
gcc –Wall pcf8591.c –o pcf8591 -lwiringPi
sudo ./ pcf8591</syntaxhighlight>


== 系列教程 ==
{{Raspberry Pi Study}}