24X8 scrolling LED Text with 3 shift registers 74HC595

Discussion in 'General Electronics Chat' started by jeshra279, Apr 4, 2012.

  1. jeshra279

    Thread Starter New Member

    Dec 21, 2011
    Dear All,
    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.

  2. Wendy


    Mar 24, 2008
    Welcome to AAC!

    Words are good, schematics are better. Show us your work.