ICM7218

                                               ICM7218                     

 

Hello world!!!!

In this page we are going to get some over look on popular ICM7218A seven segment driver IC from intersil.

Topics we are going explain are as follows:

•  How it works?
•  Interfacing with micro-controller (atmega16).
•  Cascading multiple ICM7218A.
•  Embedded C code.

 So,lets get started with working.
      It's 28 pin IC can drive up to 8 seven segments, with two control pin's it controls entire IC. off course other pins also required haa haa any way.

Control Pins- MODE(PIN NO 9), WRITE(PIN 8)
Subcontrol Pins- HEX/CODEB(PIN NO 5), DECODE(PIN 6), DATA COMING( PIN NO 7), SHUTDOWN(PIN NO 10).
NOTE: Subcontrol has dual function it can be data or mention above.

      ICM7218A

 












 it's working is very simple & as follows:
1. Set mode pin HIGH i.e '1'.
2. Set write pin HIGH i.e '1'.
3. load the control byte on ID4-ID7(load the control byte as per requirment). 
  Ex. shutdown pin signifies normal or shutdown you can choose either of this, if you want decode mode then use decode pin to do this, then you have to choose either hex or CODEB mode, if you want to send the data after control byte then use pin DATACOMING but if you use this you have to have send the 8 bytes of data after control byte.(we will see this in code). 
4.Set write pin LOW i.e '0'.
5.Set write pin HIGH i.e '1'.

That's it we set control byte & now look for data bytes.
it's plain simple just send 8 bytes on ID0- ID7 for sequentially. this data coming should be when writing control byte.(If using no decode mode other wise 4 bits will be sufficient).     


CODE

#include <mega16.h>

#include <delay.h>

#define Write_Pin            0
#define Write_Pin_Direction  0
#define Mode_Port            DDRA
#define Data_Port            PORTC
#define Set_Data_Port_Direction  DDRC=0XFF
#define no_of_digits 64
#define Count_for_one_display 0

//unsigned char display_var[no_of_digits]={0};

unsigned char Mode_Pin=0;

unsigned char Segment_code[11]={0x7B,0X30,0X6D,0X75,0X36,0X57,0X5F,0X70,0X7F,0X77};

void display_init()

{

/********* PORTC.1 & PORTC.0 is used for mode pin & write pin resp while PORTA is used for data**********/

    Set_Data_Port_Direction;

    Mode_Port=0xff;

    DDRB|= (1<<Write_Pin_Direction);

}

void Control_routine(unsigned char Control_byte)

{

    PORTA=(1<<Mode_Pin);

    PORTB=(1<<Write_Pin) ;

   // delay_ms(20);

    Data_Port= Control_byte;

   // delay_ms(20);

    PORTB&=~(1<<Write_Pin);

   // delay_ms(20);

    PORTB=1<<Write_Pin;

    PORTA=0;

   

}

void Data_routine(unsigned char Data_byte)

{

    PORTB=(1<<Write_Pin) ;

   // delay_ms(20);

    Data_Port= Data_byte;

   // delay_ms(20);

    PORTB&=~(1<<Write_Pin);

   // delay_ms(20);

    PORTB=(1<<Write_Pin) ;

    Data_Port=0;

   

}

void All_Display_Routine()

{

   

    //  Control data"normal mode , decode ,hex decode & data coming"

//     Control_routine(0XD0);

//     for(count=7;count>=Count_for_one_display;count--)

//     {

//        if(count==0)

//        {

//            Data_routine(count);

//        }

//        else

//        {

//            Data_routine(count|1<<7);

//        }

//          

//     }

    

    

    

   //  delay_ms(1000);

    

    

    

    

    }

void all_display()

{

unsigned char count,outer_count;

for(outer_count=0;outer_count<=7;outer_count++)

    {

        Control_routine(0XF0);

         for(count=0;count<=7;count++)

        {

             Data_routine(0X7B);

        }

          

        }

  }

void blink_display()

{

    unsigned char count,outer_count;

    for(outer_count=0;outer_count<=7;outer_count++)

    {

        Control_routine(0XF0);

         for(count=0;count<=7;count++)

        {

            if(count<4)

            {

            Data_routine(1<<7|0);

            }

            else

            {  

            Data_routine(0X7B);

            }

          

        }

    }

   

}

void main()

{

  //  delay_ms(1000);

    display_init();

    All_Display_Routine();

    while(1)

    {

      all_display();

    //  delay_ms(500);

      blink_display();

     // delay_ms(500);

    }

   

}

 

 Code has been tested on hardware. just play with code uncomment/ comment it will understand it.you can connect multiple max 7218 with all pins common between all 7218 & microcontroller except for mode which should be separate for each7218.

thank you for reading !!!!