[BPI-M3] BPI I2C GPIO extend Module and how to use


(BPI_Justin) #1

OS: BPI-M3 Ubuntu15.10 (Kernel3.4) Version: 1.0 HDMI


Step 1: Download WiringPI

$ git clone https://github.com/BPI-SINOVOIP/BPI-WiringPi.git111 -b BPI_M3 $ cd BPI-WiringPi $ chmod +x ./build $ sudo ./build

Step 2:Check the BPI I2C GPIO extend(PCF8574) device to see if it’s on track.(address 0x27) (I2c port number for M3: 2 )

sudo su i2cdetect -y 2

.0 1 2 3 4 5 6 7 8 9 a b c d e f 00: – -- – -- – -- – -- – -- – -- – 10: – -- – -- – -- – -- – -- – -- – -- – -- 20: – -- – -- – -- – 27 – -- – -- – -- – -- 30: – -- – -- – -- – -- – -- – -- – -- – -- 40: – -- – -- – -- – -- – -- – -- – -- – -- 50: – -- – -- – -- – -- – -- – -- – -- – -- 60: – -- – -- – -- – -- – -- – -- – -- – -- 70: – -- – -- – -- – --

Step 3 : Copy smaple code to i2c_pcf8574.c file

$ sudo vi i2c_pcf8574.c

Step 4 : Compile i2c_pcf8574.c

$ gcc -o i2c_pcf8574 i2c_pcf8574.c -l wiringPi

Step 5: Run i2c_pcf8574

$ sudo ./i2c_pcf8574


Video Demo:


Sample Code:

#include <wiringPi.h> 
#include <pcf8574.h> 
#include <stdio.h> 
int main() 
{ 
        int i; 
        pcf8574Setup(100,0x27);                                  
        for(i=0;i<8;i++) pinMode(100+i,OUTPUT);                                                                                                
        while(1)                                                 
        { 
                i = 0; 
                for(i=0;i<=8;i++)                                             
                { 
                        printf("Current LED = %d\n",100+i);                      
                        digitalWrite((100+i),HIGH);                       
                        delay(500);                                       
                        digitalWrite((100+i),0);                         
                        delay(500);                                       
                } 
        } 
   
}

Schematic diagram:

https://bananapi.gitbooks.io/bpi-accessories/content/i2cgpiomodule.html