GPIO EoF-003

Description

The "raspberry Pi GPIO Triple Expand Board" used for Raspberry Pi can copy Raspberry Pi's GPIO pin to the number of three ,in this case ,you do not worry about that some GPIO pins been occupied by external sensor modules ,you have three times of Raspberry Pi's GPIO pins

Overview

Schematic

LCD module scale

RGB1602 pin description

Learn

• If it's the first time for you to use Raspberry Pi, please make sure the I2C interface is enabled. This page will show you how to enable the I2C interface. http://www.52pi.net/forum.php?mod=viewthread&tid=1363&highlight=rtc
• You also need to install wiringPi library. This page will show you how to install wiringPi. http://wiringpi.com/download-and-install/
• If you are done install the wiringPi and enabling I2C interface, type the following code in the console to build a .c file

sudo vim.tiny lcd1602.c

• Copy and paste the following demo code into lcd1602.c

• Under the vim.tiny editor, type ":", then type "wq" and press "enter" to save the lcd1602.c file and exit editor

• Next you need to compile the code using gcc.

gcc lcd1602.c -lwiringPi /home/pi/wiringPi/devLib/lcd.o -o lcd1602

• You should find an executable file named "lcd1602" if the last step was completed. Type the following code sudo modprobe i2c-dev to load the I2C interface

• Lastly, type sudo ./lcd1602 , and the module will be displaying the demo text, as the following photo shows.

• This is a gif showing the different backlight colors

Demo Code

#include <stdio.h>                                                            //include standard input output head file
#include <wiringPi.h>                                                         //include wiringpi
#include <mcp23017.h>                                                         //include mcp23017 control head file
#include <lcd.h>                                                              //include LCD control head file
#include <softPwm.h>                                                          //include PWM control head file
int main()
{
    long value=0;
    int rand_num;
    int value_blue;                                                       //the blue backlight brightness
    int value_red;                                                        //the red backlight brightness
    int value_green;                                                      //the green backlight brightness
    int display,i,count;
    wiringPiSetup();                                                      //init wiringPi
    mcp23017Setup (100, 0x20);                                            //init mcp23017 chip I2C address: 0x20,the first pin number: 100
    printf ("Raspberry Pi - MCP23017 Test\n");                            //print information
    for(i=0;i<16;i++)
    pinMode(100+i,OUTPUT);                                                //set pin 100 - 115 as output
    digitalWrite(101,0);                                                  //set pin 101 low voltage
    display=lcdInit(2,16,4,100,102,103,104,105,106,0,0,0,0);              //lcd init 2*16,4 bit control,use 100,101,102,103,104 pin as control pin
    lcdHome(display);                                                     //reset cursor
    lcdClear(display);                                                    //clear screen
    lcdPosition(display,0,0);                                             //set display location (0,0)
    lcdPuts(display,"Hello World");                                       //print string "Hello World"
    lcdPosition(display,0,1);                                             //set display location(0,1)
    lcdPuts(display,"www.52pi.net");                                      //print string "www.52pi.net"
    pinMode(0, OUTPUT);                                                   //set Raspberry pi pin 0 as output
    pinMode(2, OUTPUT);                                                   //set Raspberry Pi pin 2 as output
    pinMode(3, OUTPUT);                                                   //set Raspberry Pi pin 3 as output
    softPwmCreate (3, 50, 100);                                           //set soft PWM pin 3 PWM scale (0-100) original 50
    softPwmCreate (2, 50, 100);                                           //set soft PWM pin 2 PWM scale (0-100) original 50
    softPwmCreate (0, 50, 100);                                           //set soft PWM pin 0 PWM scale (0-100) original 50
while(1)                                                                      //always display
{

    delay(200);                                                            //delay 200ms
        value_red=(value<100)?value:0;                                         //0-100 red change
    value_green=(value>100&&value<200)?(value-100):0;                      //100-200 green change
    value_blue=(value>200)?(value-200):0;                                  //200-300 blue change
    if(value>300)                                                          //>300 random colour
    {
        value_red=rand()%100;
        value_green=rand()%100;
        value_blue=rand()%100;
    }
    //rand_num=rand();
    softPwmWrite (3,value_red);                                             //soft PWM control red backlight
    softPwmWrite (2,value_green);                                           //soft PWM control green backlight
    softPwmWrite (0,value_blue);                                            //soft PWM control blue backlight

    value++;
    if(value>900)                                                           //if value >900 return
    {
        value=0;
    }

    lcdPosition(display,13,1);
    lcdPrintf(display,"%d",value);                                           //print number value
    //value_blue=0;

    }
}

Attachment

LCD manuals demo code