89S52 and LED 8x8 Matrix

Hello friends,

I tried to light up LED 8x8 matrix common anode,
The circuit diagram below



Why isn't it diplayed correctly, there's a "shadow" on the character and can not fix on it's place ( the column), anyone can assist me ? thanks a lot
And the code :
====
#include <REG51.H>

//#define Row P2
//#define Column P3




unsigned char pat[8] = {0x3C,0x3C,0x3C,0x00,0x00,0x3C,0x3C,0x3C}; //H


void delay_ms(unsigned int msec) //delay function
{
//;

unsigned int i,j;
for(i=0;i<msec;i++)
for(j=0;j<1;j++);

}



void main () {
unsigned int cnt, col, row ;

P1 = 0x00 ; /* Initialize all P1 outputs to be low */
P3 = 0x00;
while(1)
{

for (cnt = 0 ; cnt < 8 ; cnt ++ )
{
row = 1;
//for (col = 1 ; col >0 ; col<<= 1)
for (row = 1 ; row < 0xFF ; row<<= 1)
{

P1 = ~row; // try to reverse the port ?
P3 = pat[cnt];

delay_ms(2) ; // delay of 1 ms
}
}


}
}

Have you used any device between the mcu and the leds to handle the increased current?
Your mcu can't drive them directly, the output current capacity is very low.

Alex

alexan_e said:

Have you used any device between the mcu and the leds to handle the increased current?
Your mcu can't drive them directly, the output current capacity is very low.

Alex

Click to expand...

Yup I put PNP transistor 2N3906 to drive the row,
Can you assist me with the "shadow" ? thanks