I am designing a video adapter that I intend to run from the output of the TTL LCD output port of an iMX6Q Wandboard. But before I get started, I would like to ask a few questions.
1.) What is the maximum resolution achievable over the TTL port? According to the reference manual (IMX6DQRM.pdf page 2699) the parallel port supports SMPTE274 (1080i/p), which is the exact format that I need. However most of my experience with this type of interface has been with very small LCDs. Can anyone confirm that the 1080i/p standard is achievable?
2.) Currently I have just the TTL port enabled by adding to the console parameter: 'video=mxcfb0:dev=lcd,1920x1080@60,if=RGB24'. I can measure data off the pins at the right times, but the pixel clock is not correct. I believe this is due to my u-boot settings, specifically using RGB24. If I intend to use the 20-bit YCrCb mode, what would be the appropriate setting? Is there a table of all acceptable display settings in a reference manual that I can read?
3.) Displaying over HDMI and TTL at the same time should be possible. I assume the u-boot settings would look something like: 'video=mxcfb0:dev=lcd,1920x1080@60,if=see_question_2 video=mxcfb1:dev=hdmi,1920x1080M@60,if=RGB24. Does it matter which frame buffer a display is on? What would happen if I swap them so that HDMI is on fb0 and LCD is on fb1?
4.) I am tinkering around with the idea of adding a small LVDS touch-enabled screen to my project as well. This would be intended to display something else than what is on the HDMI and TTL LCD. What will the u-boot settings look like then? I have seen these three displays all operating this way before, but I am not sure how to replicate that setup.