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AM3358: LCD LIDD DMA issue

Anand Kumar6
Prodigy 150 points
Part Number: AM3358


Hello,

I am using a character LCD 16 x 2 to display. I am using the LCD LIDD in DMA mode.

The characters do appear well and clear.

However sometimes (maybe (3/10) cases), I see only portion of the text appearing on the display. During other times, the complete set of character text is well displayed on the LCD.

Eg: I want to display 123456789;

Before every write to the LCD, the display is cleared. Whenever I write ( (7/10) cases) the display shows 123456789;

However, (maybe (3/10) cases), the display shows 1        

I feel the DMA was not able to output the full buffer content into the LCD as it got blocked with some other CPU activity.    

Is this to do with some synchronisation errors or DDR-LCD bandwidth?

I even tried to set the EMIF registers of OCP_CONFIG to 0x00141414. I also tried values 0x00F0F0F0. This I tired because I thought it was something to do with DDR-LCD bandwidth.

But it didnt help.

Please help in resolving this issue.

Regards

Anand

  • 0
    Prodigy 150 points

    Dear All,

    Its seems the problem has been resolved after having changed the DMA clock frequency.

    I have increased the clock frequency from its previous values and now it is working fine for me.

    I get all the characters displayed on the screen every time I write something to it. So looks good.

    Thanks & Regards

    Anand