A flow chart of the HDMI display software might help novices understand what the HDMI program(s) do and why they do it. In particular I'd like to know how the buffer is organized and how to put information in it pixel by pixel so I can see it on the LCD. How can I display only a small green square on the LCD?
For a good diagram the shows and explains a bit-mapped image file, visit: https://engineering.purdue.edu/ece264/16au/hw/HW13.
That is better (mostly on) but if I try another 8bpp BMP it stops working, all the time it works on my main monitor (even with the alternative BMP) but not on the 7"
An interesting tutorial would be to show how in code, to place a pixel of a specific color at an x,y coordinate on either an HDMI or VGA display. Wouldn't that be a "core" function for teaching basic graphics that can be extended to create lines & more complex shapes? All examples so far seem to be at such a lower level than "mere mortals" like myself can use to display basic graphic items.
dgately
Have you looked at the mandelbrot and/or turtle_demo samples that come with FlexProp? Both of those plot pixels, the mandelbrot in 8 bit and the turtle graphics in 16 bit.
... My pin group is the same as yours (48), I know it's right because I've plugged into my monitor and it's fine.
This problem is more related to the 7" screen I think, maybe it's on the edge of it's tolerances.
... My pin group is the same as yours (48), I know it's right because I've plugged into my monitor and it's fine.
This problem is more related to the 7" screen I think, maybe it's on the edge of it's tolerances.
What is the native resolution of your 7" LCD?
800x480, the BMP and Driver are the same resolution.
Not sure what refresh rates it can handle and I suspect that's where the issue lies.
@Ariba figured out that the LUT starting from index #32 was due to the xcont line having a source value of 1 instead of 0.
Here's an update with that fixed.
@Coley Comparing with the Spiral demo, I think I may have had the vertical blanks top and bottom reversed...
Can you try this version and see if it's any better?
Wait a minute... This doesn't work with my LCD... I'll keep looking...
Actually, it does work on mine... Didn't have the extra power connected...
An interesting tutorial would be to show how in code, to place a pixel of a specific color at an x,y coordinate on either an HDMI or VGA display. Wouldn't that be a "core" function for teaching basic graphics that can be extended to create lines & more complex shapes? All examples so far seem to be at such a lower level than "mere mortals" like myself can use to display basic graphic items.
dgately
Have you looked at the mandelbrot and/or turtle_demo samples that come with FlexProp? Both of those plot pixels, the mandelbrot in 8 bit and the turtle graphics in 16 bit.
Thanks for the reminder! I'll go back and check them out... In the mean time, I got simple line drawing working (and... now Ray has a lot more simple drawing code woking). Lot's of example code to work from!
Comments
The image does appear, albeit very briefly ;-)
For a good diagram the shows and explains a bit-mapped image file, visit: https://engineering.purdue.edu/ece264/16au/hw/HW13.
@JonTitus This version draws a rectangle on top of the image. Maybe that will get you started...
It's a strange one.
Try this:
I think this is what it actually should be.
Working better now, still not 100% stable.
Have you looked at the mandelbrot and/or turtle_demo samples that come with FlexProp? Both of those plot pixels, the mandelbrot in 8 bit and the turtle graphics in 16 bit.
800x480, the BMP and Driver are the same resolution.
Not sure what refresh rates it can handle and I suspect that's where the issue lies.
Here's an update with that fixed.
Can you try this version and see if it's any better?
Wait a minute... This doesn't work with my LCD... I'll keep looking...
Actually, it does work on mine... Didn't have the extra power connected...
I've found the difference between the spiral demo and your code it's this line in the setup of the spiral demo
Your code is this line
Rock steady on the 7" LCD now ;-)
Hopefully, this is the last version of this.
It's all good!