Just a quick question: Is there a way to determine the tile colors (FG/BG) in Mode 1 on the Picomite HDMI?

Regards
MIchael
Edited 2026-06-27 13:25 by Grogster

G'day,
This is possible but not directly with a command AFAIK. At some point I had a need to read from the framebuffer to drive a display not supported by the firmware, you can read the colours of the FG/BG (Mode 1) out of the framebuffer in HDMI:

Using 1024 x 600 resolution:

? Hex$(mm.info(writebuffer))
2003BA00 ' Framebuffer Base Address

&h2003BA00 + 76800 = &h2004E600 ' 1024 x 600 @ 1bpp = 76800Bytes

&h2004E600 is start of Foreground Colour Buffer, 1 Byte per Tile.

&h2004E600 + 9600 = &h20050B80 ' 1024/8 * 600/8 = 9600 Max Tiles @ 8*8

&h20050B80 is start of Background Colour Buffer, 1 Byte per Tile.

Using PEEK and these base addresses you can find the colour of any tile.

This will all change depending on mode, resolution and if framebuffers l/f exist.

Hope this helps.

Regards, Lyle.
Edited 2026-06-26 00:30 by mozzie

Hi Lyle,
Thanks for your reply. That’s exactly what I was looking for and hoping to find. I remembered seeing something like that before but couldn't find it in the manual.
I’ve already experimented a bit, though unfortunately without success so far. At least it’s a good starting point, and the rest will fall into place.
Thanks again for your effort and the detailed explanation!

Kind regards
Michael

PS: I’m just wondering who changed the thread title ("A way to determine the tile colors in Mode 1?")... Russian hackers?

twofingers,

Depending on what you need the info for,, there may be a better way.

If you are running an MMBasic program, and need to know tile color, the best way is to remember, since your MMBasic program did set the tile color itself.

If you have a shared memory application: the PEEK above is your best solution.

But...if you want to work on this tile data from a PC there is another way.

- in the program that set the colors: SAVE IMAGE (or SAVE COMPRESSED IMAGE)
- transfer to the PC
- open the image in PAINT, PHOTOSHOP or your favorite picture editor

The SAVE IMAGE contains all color information. See below, a picture from 640x480 logic analyzer screen that works with tiles. As opened on the PC.





But you have to save from the running program. When you stop the program, tile information is not saved.

Volhout

P.S. thanks to Peter, who added this functionality in 6.01, Tested on VGA.
Edited 2026-06-26 06:20 by Volhout

Not tested with Tiles but perhaps reading from the screen buffer will work.


Edit.
Tested in Mode 1. The foreground and background colours of the tiles are read correctly.

A little shorter.
Edited 2026-06-26 11:59 by phil99

  phil99 said  

A little shorter.

> pixel 1,1,1 : tile 0,0, RGB(255,0,0), RGB(0,128,255)
> z = pixel(1,1) : ? z >> 16; z >> 8 And 255; z And 255
255 0 0
> z = pixel(0,1) : ? z >> 16; z >> 8 And 255; z And 255
0 128 255
>

However, this only works if the second pixel (BG) being checked is not set. So it’s more a matter of chance and isn’t reliable.
The method using `Peek` seems to be more reliable.
(Unfortunately, I can’t test it at the moment because my new monitors are still in the post)
Cheers
Martin
Edited 2026-06-26 16:17 by Martin H.

Question is "why would you try to find the color of a pixel/tile that you just programmed yourself". ?
Since MMBasic is single thread, nobody can program the tile except you yourself. And in MODE1 the tile information is lost when you exit the program to a different one.

Volhout

  Quote  

However, this only works if the second pixel (BG) being checked is not set.

Fair enough, set that pixel to 0 first.

Despite Volhout's perfect logic here is version 2.

Or recycle the same pixel.
Edited 2026-06-26 18:25 by phil99

Footnote added 2026-06-27 10:30 by phil99
This is redundant now but saves and restores the test pixel.

  Volhout said  

twofingers,

Depending on what you need the info for,, there may be a better way.

If you are running an MMBasic program, and need to know tile color, the best way is to remember, since your MMBasic program did set the tile color itself.

Hi Harm,
thanks for the suggestion. That is exactly how I handle it in the FM: I store the relevant data in a 2-byte array. However, for the specific purpose at hand, I do not want to allocate a new array. That consumes too much precious memory, and I only need to save and restore a small segment. Keep it simple.

I assumed that for the mentioned Mode 1 with 640x480/8 bytes, the pixel memory (mono) starts at the address pointed to by MM.info(writebuff), followed by 80x40 bytes for the foreground and background colors of the 'tiles', with 4 bits for the foreground and 4 bits for the background (compactly stored in a single byte).

That assumption was likely incorrect. I now believe that the color information for tiles is inaccessible (unless it is being "logged").

Thanks also to Phil and Martin.

Michael

Michael,

The tiles not necessarily are arranged as 80x40, since that implies tiles are 8x12. And they can be anything from 8x8 to 8x480.

That reminds me that there is an error in the manual (multiple locations, copy-paste).

tile height is up to MM.VRES (not HRES)




Regards,

Volhout
Edited 2026-06-26 19:02 by Volhout

G'day Michael,
Found some notes related to this, this was 640 x 480 HDMI Mode 1:

&h2003BA00 = Main Buffer found with ? HEX$(mm.info(writebuff))
+ 38400 Bytes = 640/8 * 480
&h20045000 = Frame Buffer
+ 38400 Bytes = 640/8 * 480
&h2004E600 = Layer Buffer
+ 38400 Bytes = 640/8 * 480
&h20057C00 = F-Colour Buffer 2 bytes per Tile (RGB555?)
+ 9600 Bytes = 640/8 * 480/8 * 2Bytes
&h2005A180 = ???????? Maybe L/F Buffer colours ????????
+ 9600 Bytes = 640/8 * 480/8 * 2Bytes
&h2005C700 = B-Colour Buffer 2 bytes per Tile (RGB555?)

This seems to be consistent with a couple of modes, 1024x600 is different.

There is a program here somewhere that interrogates the memory to figure out where things are hiding, sets a FG/BG colour and then goes looking for starts and ends.

Also not sure what happened to the thread title, but its not the first time its been mentioned that this can happen.

Regards, Lyle.

Edit: Defective math  
Edited 2026-06-26 22:20 by mozzie

  twofingers said  

PS: I’m just wondering who changed the thread title ("A way to determine the tile colors in Mode 1?")... Russian hackers?

Sometimes the forum software does odd things like this.
Gizmo could possibly say why that should have happened in your case, but for now, I just edited your thread to put the full title back in.  

I DID wonder myself about the odd thread title when I saw it.....