Info needed about DCU4 on vybrid platform

[prasanna_nandar]

Hello,

This is with reference to Vybrid of Vybrid Display Control unit. In the overview there diagram there are 64 layers shown and also there are 6 FIFO show. It is NOT clear from the document that how these 6 FIFO are used in the system apart from or along with 64 Layers. Also please let me know how these FIFO are different from those 64 layers.

NOTE: Please let me mention I have been following Freescale from 2005 with iMX processors. I am not sure whether I am the only person who is experiencing this but somehow I felt that the Vybrid documentation quality and completeness is not as it used it to be earlier with other Reference Manuals. For example there are mentions about DCU3 and AXI in the documentation but there is No proper explanation about these terminologies. And another example is the overview sections say "This comprises two distinct sections" but there is not clear demarcation of these sections. And sometime it is difficult to relate these 'upper and lower sections' as referred by the document.

Thanks and regards,

Prasanna

[ioseph_martinez · Accepted solution]

Prasanna,

Layers represent objects, you can have 64 on screen. Planes/FIFOs represent pixel blending capacity. Imagine you have 64 layers on top of each other, only 6 first layers would be blended and each layer pixels would go to those FIFOs. Those layers would need to be transparent in order to be blended. I added an slide from a previous deck from FTF 2012 which may make this a bit more clear. I would like to point out that you do can have 64 object simultanously, the limitation blend up to 6 only comes up when you have overlapping with transparent component layers.

Regarding your comments about the documentation, I will take a look and add some notes on the draft version where appropriated based on your feedback. Feel free to let us know any other findings you think we should be looking at.

Ioseph