stm32f439i LCD(800*600) display run in 16bit sdram

[liangbing119]

Posted on March 21, 2016 at 10:56

sdram clock run in 90MHz;LCD clock run in 24MHz.it not work(display ng).but LCD clock run in 18MHz,it work(display ok),but it looks blink,because reflesh rate low.

huw to solve it?

[Radosław]

Posted on March 21, 2016 at 13:19

800*600*4 *25 =  48MB/s

16bit SDRAM  90MHz  -> ~150MB/s.  Simply math.  Only for read.  Quite big bandwith LCD uses.

[liangbing119]

Posted on March 22, 2016 at 02:33

Yes,I think so.But LCD clock run in 18MHz(18M/800/600=37.5),less than 37 frames(true 18M/1000/660=27 frames,it looks blink),LCD bandwith 18M*24bit=54MB/s,I want 50 frames/s,LCD clock will set in 33MHz(bandwith 800*600*3*50 = 72MB/s).But LCD clock run in 20M,display unreadable code.

How to solve it?