BT815 to HDMI or VGA

[FlorianG]

Hi everybody,

I will need to pass the image of the BT815 on a HDMI or VGA cable.
is there a solution to this problem?
It should transform the 40pin parallel RGB image to HDMI or VGA.

I heard about the screen drivers but I did not find anything about it.

Thank you in advance for your help.

[BRT Community]

Hello,

Unfortunately I do not have any suggestions for an applicable translation IC, but maybe someone lese on the forum can point you in the right direction.

Best Regards,
BRT Community

[Rudolph]

You could try to contact these guys:
https://blackmesalabs.wordpress.com/2015/08/30/mesa-video-800x600-digital-video-for-arduinos-over-2-wire-serial-mesa-bus/

I am not sure though if this is available, at least there is nothing for this project on the github repository.
https://github.com/blackmesalabs

[FlorianG]

OK, thank you for your reply.

if I understand correctly it is the TFP410 that will be responsible for converting the video signal of the BT81x or FT81x into HDMI signal.

[Matrix Orbital]

OK, thank you for your reply.

if I understand correctly it is the TFP410 that will be responsible for converting the video signal of the BT81x or FT81x into HDMI signal.

FlorianG, can you explain why you are trying to do this?

[FlorianG]

Yes, I would like to be able to capture the video output of the BT815.

And why not use it as an HDMI arduino graphics card. But it's segundary.

The problem is that the maximum definition of BT815 is 800 * 600 or 1280 * 800 ( https://brtchip.com/Brochures/BT815_6%20Demosheet.pdf )
and not 1920*1080.
but it's not a major problem.

I'm thinking about how to couple 4 bt815 that can display 1080p but I do not see how to do. It could be super cool

[AT38]

I'm thinking about how to couple 4 bt815 that can display 1080p but I do not see how to do. It could be super cool

Square peg, round hole. But if you wanted to engage in techno-masochism, you might consider the following:

Use a single external oscillator to drive all four BT815s
Logically OR together the RGB lines.
Connect MISO for only one BT815 (or add logic so that if only one CS is active, that MISO is connected).
Setup each one to draw 1/4 of the screen(540p). Set the front/rear porch times for each one so that each 1/4 screen is offset in the overall frame(1080p) position.

Code Select Expand


  v Display1 area
_____________v horizontal rear porch
|/----\      |
|\----/      |
|            |
|____________| < vertical rear porch

        v Display2 area
_____________v horizontal rear porch
|      /----\|
|      \----/|
|            |
|____________| < vertical rear porch

  v Display3 area
_____________v horizontal rear porch
|            |
|            |
|/----\      |
|\----/______| < vertical rear porch

        v Display4 area
_____________v horizontal rear porch
|            |
|            |
|      /----\|
|______\----/| < vertical rear porch


Enable CS for all 4 BT's and enable the pixel clock. All things being good and deterministic, they should all be synced with each other,
but producing output in different quarters of the screen.

Each BT will need its own unique display list with all coordinates offset according to it's position in the output frame.
To maintain synchronisation it will probably be necessary to send the SWAP command to all 4 BT's at once.

HSYNC and VSYNC pulses should be the same on each one, so no need to OR them (just use one set).
Chopping the screen vertically 4 ways may be better than 2x2, because variations in timing will have less impact on a line-by-line basis compared to pixel-by-pixel...
...assuming the timing parameter values can be set appropriately (for any of this).

This is a terrible idea and probably won't work.
But if you really wanted to try it, this is the best approach I can think of.
If you make it work, send me pics 

[FlorianG]

"Setup each one to draw 1/4 of the screen(540p). Set the front/rear porch times for each one so that each 1/4 screen is offset in the overall frame(1080p) position."

That's what I missed.

Thank you very much, I do not know when I will test it but there is a good chance that it will happen