Circuit file

#include<at89x52.h>
sbit DATA = P0^0;
sbit SCK = P0^1;
sbit SCL = P0^2;
	unsigned char code hang[]={
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xC3,0xBD,0xBD,0xBD,0xBD,0xBD,0xBD,0xC3,
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF
	};
unsigned char cot[8]={0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01};
int n,k;
void delay(unsigned long time)
{
	while(time--)
	{
		_nop_();
	};
}
void quet(unsigned char x)
{
	unsigned char i, temp;
	for (i=0;i<8;i++)
	{
	SCK	= 0;
	temp = x;
	temp = temp&0x80;
	if (temp==0x80)
		DATA = 0;
	else DATA = 1;
	x*=2;
	SCK = 1;
	}															 **
}
void main()
{
	while(1)
	{

	for(n=0;n<8;n++)
	{
	SCL = 0;
	quet(0xFF);
	quet(0xFF);
	quet(0xFF);
	quet(hang[4*8 + n]);
	P2 = ~cot[n];
	SCL = 1;
	}
	}
}

I'm working on how to use 89x52 and 74HC595 to multiplex a 8x32 LED matrix. I was able to use column scanning method, but when I changed to row scanning, it went awful. Even when I remove the delay, it still scans really slow. Is it because of my circuit design ? I need help. Thank you in advance.
P.S: I want to master both row and column scanning so, please, don't suggest using column scanning...

 

Hello,

I do not see anything at the link.
Please upload the circuit to the forum.
See here how to do that:
Attachments and Images

Bertus

 

My bad... I mistyped the link. Here is the correct one: http://www.mediafire.com/?q99mt2jlxj0mfy1
P.s: Do you have Proteus? I can upload a picture if you want

 

can anyone please indicate what the problem is?

 

your proteus version is higher than mine so I cant open your DSN file.

You can go to "\edit\copy to clipboard" then open with "paint" and save the picture as .PNG file and upload it here so others can see your schematic.

Not everyone uses proteus here.

Like this.....

Allen

 

Here you go

 

Oh god, I just realized the reason why it scans so slow. My CPU cannot handle the simulation, so it takes a whole minute to animate 1 sec. Well, I still need somebody to check my schematic though. Thank you.

 

Are the values of resistors properly calculated? I am going to assemble everything soon

 

I'd put 1K resistors between the base of Q1-Q8 to port 1 pins.

D1 would be quite dim with 2.2K resistor. Was it used as a power on indicator?

Allen

 

yeah, it's the power indicator. And you are right, I am gonna change the indicator's components into a red LED and a 320 ohms resistor, all of the circuits use a 5V power supply. Does that sound fine? I am rechecking the transistor properties... It' a little confusing ...

 

Yeah, I agree, I'll change all the values of R10-16 to 1K. Thank you.

 

I would remove all the resistors and use digital MOSFETs instead.

For the software, use a memory image of the matrix, then only update one scanline each refresh cycle. If you want to swap X/Y, you need to remap the data from the memory image.

 

Is it necessary to use MOSFETs? I know MOSFETs can work exponentially, but what's wrong with transistors?

 

They drop too much voltage and need resistors.

http://www.nxp.com/products/mosfets/standard_mosfets/2N7002.html#overview

not difficult to use, and not expensive at all.
Yes you can use BJT, but I never use them for LED matrix, only once (with undesireable results).