Dot Matrix

what kind of controller are you using? are you using a led matrix or individual multiplexed LED's? more info please

oh sorry i forgot to mention.

i am using Atmel 89s52 and yes i am using led matrix.

you got to check with the manufacturer of such matrix, for them to provide the control code!

Please give the manufacturer and part number of your display device (LED array).

What type of microcontroller you have ?

here are some examples

http://www.mat.ucsb.edu/200C/2008_Students/MAT-200C_2008_Files/matt_stabile/MAT200CStabile.pdf

http://www.youtube.com/watch?v=GHzznKk8fmA

http://www.embeddedmarket.com/products/Practical-Course-For-ATMEL-Microcontrollers-Upgraded/LED-Toggle-Using-Switch-For-8051/

i just glanced at it but it may have some useful info.

Hi there I did a similar thing with a picaxe 28x chip and no driver circuitry or resistors (the pic didn`t blow up and worked quite happily) so it was relatively simple but not quite as bright as the commercial displays. Basically you use one of the microprocessor ports to drive the outputs or columns in the display and you wire all of the rows to another port also configured as output . So for an 8x8 array sending binary 10000000 to the output port a (columns) and 11111110 to port b (rows) will light 1 of your 64 leds. To get patterns manipulate the output and inputs e.g port a = 255 (11111111) and port b 0 (00000000) turns all 64 leds on. However you will soon see that certain patterns are not available directly so you must drive each column one at a time in a loop whilst feeding in the row information for that character as an 8 bit number. I used the memory on the chip to store the data and then read it in using a read or peek command. Likewise I wrote a program to convert the patterns to binary on a PC. If you want to get more complex you must use driver chips, serial data and shift registers so it can get very messy for a beginner.

http://www.youtube.com/watch?v=WRVsccpUWmA

This shows a 7x5 and 4x4 arrays I used some time ago.

Shows what you can do with minimum equipment but as for programming in C your on your own there I used basic.