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Moving LED display with 4 shift Registers 74HC595

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rajesh279

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Dear All,
I have 4 shift registers for 32 columns and 8 rows are directly connected via Port A of Microcontroller.
I have to activate each row one by one and feed all the 32 columns data and then latch them.

The problem is:
1) how to send 32 bits for 32 columns one bye one, and

2) How to create scrolling effect from right to left...? e.g. if 1st 8 bits is loaded with some character to be displayed, then at next instant 2nd 8 bits will hold the 1st 8 bits' data and 1st 8 bits will now be loaded with new character.

I hope the problem is clear. Basic idea is how to create scrolling effect.

Any suggestion/help would be highly helpful.

Regards
Raj S
 

24X8 scrolling LED Text with 3 shift registers 74HC595

Hi,
I am already having a hardware with 3 shift registers 74HC595. So there are 24 columns and 8 rows.
I have a character matrix for alphabet 'D' as

unsigned char MyChar[8]={0x7c, 0x42, 0x42, 0x42, 0x42, 0x42, 0x42,0x7c}

The 8 hex values corresponds to 8 rows of the matrix. Now I want to scroll the 'D' from right to left.
From my knowledge, I know that I have to prepare 24 columns(i.e. 24 bits) data to load while switching the rows.
This I can make in a loop like:

for(i = 0; i<3; i++)

DisplayBuffer =.....

}

now, once the DisplayBuffer[] is created, I can load them on the corresponding rows.
But I am stuck in how to create and update these DisplayBuffer[] while scrolling the text.

Any help would be appreciated.

Regards
Raj.
 

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