DCU4 on Vybrid with D4D

[alansinicki]

I have a mostly working implementation of DCU4 on the M4 side of our Vybrid processor using D4D.  However I'm seeing some pixel data being lost.  I'm confident it is not a timing issue with the LCD as the Color bars display correctly with the DCU4 in Mode 0.  It looks as if some of the data is being lost or not correctly placed in the framebuffer by the D4D low level code.  Any ideas or advice would be welcome.

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[jiri-b36968]

Hello Alan,

pictures look exactly like timing issue. What do you mean by D4D?

It can be timing issue due to setting of the display or timing issue of transfer data between source and DCU. Are those pictures static or it is animation?

Please try to display simple static picture from GRAM or SRAM memory.

You can use Vybrid sample code together with TWR-VF65 tower module (reference board) and TWR-LCD-RGB.

/Jiri

[alansinicki]

Hello Jiri,

The pictures are static, we use D4D(egui) to draw the images into the frame buffer and let the DCU transfer the image to the LCD.  I am using a modified version of the D4D(eGui) frame buffer example.  Simple static images show the same pixel errors, however the DCU colorbar test works correctly so I believe that the DCU hardware timing is correct for the LCD panel. 

Thanks,

Alan

[jiri-b36968]

Hello Alan,

eGUI is D4D right. It is long time from my last experience. If I remember well eGUI used just one layer and one buffer. So it was not possible to display one image and prepare another in the memory.

Do not know what setting is used in eGUI. Did you tried sample code + TWR-VF65 and then your board?

It could indicate timing issue due to bandwidth limitation during transfer of image to DCU. Where are images stored? GRAM or SRAM? Please check the underrun flag (UNDRUN - DCUx_INT_STATUS).

/Jiri