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About dropout of VSYNC and HSYNC for LCD of i.MX25

Question asked by yuuki on May 29, 2015
Latest reply on Jun 18, 2015 by igorpadykov

Dear all,


We connect an LCD panel to i.MX25.
(LCD:  688 x 600 / 24bpp / 44.3MHz)


We have the problem that a noise is over to LCD.
A white line and a black line are displayed.


We checked a waveform of VSYNC and HSYNC.
We found the waveform of VSYNC and HSYNC dropouted.


[VSYNC]   Blue: VSYNC / Aqua: DE



[HSYNC]  Blue: HSYNC / Aqua: OE / Red: LD



When dropout of VSYNC and HSYNC occurred, it seems that underrun error occurs.


Can the underrun error become the cause that dropout of VSYNC and HSYNC occurs?

If it is Yes,
May I have advice about a method avoiding Underrun error?


Best Regards,