To know about Interfacing Dot Matrix led Display with PIC Microcontroller, we have to know about what is Dot Matrix Display? And how it work? Dot Matrix Display is an array of LED situated in a form of Matrix. See the architecture of a 7*5 Dot Matrix led Display board.

 Interfacing Dot Matrix led Display with PIC Microcontroller

Project Description :

In this tutorial project we can see how easily we can display any alphabet in 7*5 Dot Matrix led Display board. Let we have to display letter “C” in 7*5 Dot Matrix led Display board. Now look on 7*5 Dot Matrix led Display board it has 7 rows and 5 columns. And see the every Diode connected between raw and column if raw get positive and column get negative then only particular LED will glow. Let suppose we have to glow LED connected between R5 and C1 from above picture. So we have to send 0010000 on raw and 01111 on column. Now let for display letter C which type of data we have to send

Step 1: In Raw = 0111110

             In Column= 01111

Step 2: In Raw = 1000001

             In Column= 10111

Step 3: In Raw = 1000001

             In Column= 11011

Step 4: In Raw = 1000001

             In Column= 11101

Step 5: In Raw = 0100010

             In Column= 11110


For display complete alphabet “C” we have  to send those data with minimum delay to display at once.

 Interfacing Dot Matrix led Display with PIC Microcontroller

 

Another important think we have to keep in mind that for displaying column we need high current. because see in step 1 we are sending 0111110 so all 5 LED which have to glow in a same column so we need high current to glow all LED at a time. For this purpose we can use ULN 2003a IC which has seven built-in Darlington transistor arrays. It can provide 50volt and 500mAmp current in single chanel. In bellow I give the simulation circuit diagram In Proteus.

 Interfacing Dot Matrix led Display with PIC Microcontroller

In bellow you will see the complete C code of this tutorial Interfacing Dot Matrix led Display with PIC Microcontroller for display Character “C”.

 

Embedded C Code
// Name : Interfacing Dot Matrix led Display with PIC Microcontroller
// Author : Subham Dutta
// Date : 12-03-14
// Website : www.nbcafe.in
int b[5 ]= {65,62,62,62,93};
int ch[10 ]= {254,253,251,247,239};

void main() {
int i;
trisb=0;
trisd=0;
while(1)
{

for(i=0;i<5;i++) { portb=b[i]; portd=ch[i];delay_ms(3); } } }