Forum comments in chronological order

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Sep 2008

Craft

Anonymous
Mon 1-Sep-2008 08:11
Very nice work!!! What is the programming software/compiler you used for your source code?

The remote control project

lft
Linus Åkesson
Tue 2-Sep-2008 07:45

basafa wrote:

Can you send me circuit & Atmega88 source program of your remote control project ?

Thanks for showing an interest in my project!

Unfortunately, the remote control project is somewhat ad hoc, and has evolved
since I described it on this page. It would be difficult for me to create a
useful software/schematic combination at this point.

Craft

lft
Linus Åkesson
Tue 2-Sep-2008 07:50
Very nice work!!! What is the programming software/compiler you used for your source code?

That would be the AVR port of the GNU toolchain. During early development I used C routines (compiled with avr-gcc) along with the assembly code. Have a look in the makefile for all the details.
Anonymous
Fri 5-Sep-2008 13:36
Hi lft!

I'm very much impressed by your work! I would like to ask a question:
Since you obviously have the knowhow to produce graphics and the VGA signals at the same time, would it be possible to create some kind of simple vga-driver for the MEGA88 in a way that you can set some graphic elements on the screen using a I²C or RS232 interface?
What I would like to see is a lib for the MEGA8. We just flash it and can do the following for example:
- setPixel(x,y,color)
- setCircle(x,y,radius, color, bfill)
- setText(x,y,cString, color, ...)
- other handy stuff

I know that communication between µC use a lot of time, but there is no need to have an ultra steady vga signal using a TFT? So we could transfer some instructions and the MEGA8 would display the data on the VGA-Panel. A couple of FPS per second would be enough.

Would that be possible?
Anonymous
Fri 5-Sep-2008 19:28
An AVR console using NES controllers and NTSC Composite Video output.

-> http://belogic.com/uzebox/
lft
Linus Åkesson
Sat 6-Sep-2008 14:24
... would it be possible to create some kind of simple vga-driver for the MEGA88 in a way that you can set some graphic elements on the screen using a I²C or RS232 interface?
What I would like to see is a lib for the MEGA8. We just flash it and can do the following for example:
- setPixel(x,y,color)
- setCircle(x,y,radius, color, bfill)
- setText(x,y,cString, color, ...)
- other handy stuff

Hi! The main problem with this approach is that the chip would have to keep track of a frame buffer. 1 kB of RAM is not a lot. Even if we opt for a simple black and white bitmap, there would only be room for 128 x 64 pixels. One alternative would be to use a tiled display, but without external RAM it would still be very limited.

Once we start using external RAM, we can do lots of things, and that area has been explored by others in several projects.
Anonymous
Sat 6-Sep-2008 17:56

lft wrote:

... would it be possible to create some kind of simple vga-driver for the MEGA88 in a way that you can set some graphic elements on the screen using a I²C or RS232 interface?
What I would like to see is a lib for the MEGA8. We just flash it and can do the following for example:
- setPixel(x,y,color)
- setCircle(x,y,radius, color, bfill)
- setText(x,y,cString, color, ...)
- other handy stuff

Hi! The main problem with this approach is that the chip would have to keep track of a frame buffer. 1 kB of RAM is not a lot. Even if we opt for a simple black and white bitmap, there would only be room for 128 x 64 pixels. One alternative would be to use a tiled display, but without external RAM it would still be very limited.

Once we start using external RAM, we can do lots of things, and that area has been explored by others in several projects.

If the problem with the above is just the 1K RAM, would a larger chip with, say 4K RAM, be enough to do some basic text and graphics? Thank you for your participation.
Anonymous
Sat 6-Sep-2008 18:14
I posted the above question and just realized that 4K would only allow 512 x 256 pixels, so how about some of the 8K RAM processors? Would that allow some basic text and graphics capabilities using serial port for video data input? Thanks again!
Anonymous
Sat 6-Sep-2008 19:43
My initial idea about the setPixel and stuff was to keep track about how things are created. Not storing the actual image.
If you want to set a pixel you check if the pixel should be painted by searching some kind of ObjectPaintInstruction-stack or something.

I have to add that this approach would loose speed the more objects are to be displayed.... hmmm... maybe a dedicated VGA driver chip would be the easier choice ;)

Binary Art

Anonymous
Mon 8-Sep-2008 13:20
Clever :)

Someone should print this and show it to the Microsoft lawyers, just to see their faces after they've first laughed at it and then given that laugh a second's thought.

Autosokoban

Anonymous
Mon 8-Sep-2008 13:28
I was looking at level 100 and above, and they were pretty mean. I hope I didn't suffocate your web server with generating them!

How fast is the solving algorithm, and how does it compare to that in the original paper which inspired you, and how quickly can it (your own algorithm) solve f.ex the typical level 100's on a given system?

Reverberations

Anonymous
Thu 11-Sep-2008 11:21
I find it unfortunate that you didn’t also put up unprocessed files – that would have been extremely interesting.

Still though, this is really awesome. Thanks for sharing.

—ap
Anonymous
Fri 12-Sep-2008 02:11
I'm assuming this uses modern equal temperament? [half step up = x * 2^(1/12) ]

You should experiment with some temperaments that were popular during Bach's time.

-Andy
Anonymous
Fri 12-Sep-2008 13:03
> Well, actually it will, if you remove the church.

I'm still laughing at this :-)

The result is impressive. Thanks man.

Pygy
Anonymous
Sat 13-Sep-2008 04:33
This is lovely. Thank you very much for sharing. Of course I too would like to play with the original files, but I'm glad you've seen fit to share even the MP3s. Do we have a license to copy them around as well?
Anonymous
Sat 13-Sep-2008 04:56
This is lovely. Thank you very much for sharing. Of course I too would like to play with the original files, but I'm glad you've seen fit to share even the MP3s. Do we have a license to copy them around as well?

Oops, forgot to sign that — I'm Kragen Javier Sitaker, kragen@canonical.org.

A case against syntax highlighting

Anonymous
Sat 13-Sep-2008 05:17
It surprises me that this topic generates so much heat! It's not as if Linus is threatening to take away your syntax-highlighting, is it?

I do think that syntax-highlighting traditionally tends to put emphasis on the wrong things — boldfacing language keywords and the like — but I do find it useful; I can follow the syntax more easily, which lets me focus my attention on the semantics of the program. I think comic books have shown that doing something similar to syntax highlighting on English text, by boldfacing the words that carry emphasis in the sentences, also improves readability.

You can see some of the kind of syntax-highlighting I favor at http://canonical.org/~kragen/sw/urscheme/ — comments and “noise words” like “if” are faded out a bit, and the names of functions being defined are in a conspicuous blue color which makes it easy to scan for them (rather like boldfacing a header or a term being defined). I could improve on this (it’s just Emacs’s default syntax highlighting) but it's pretty good already. The extras in the vim example in the article don’t add a great deal, to my eye, although they don’t seem quite as distracting to me as to Linus.

— Kragen Javier Sitaker <kragen@canonical.org>

Autosokoban

lft
Linus Åkesson
Tue 16-Sep-2008 22:02
I was looking at level 100 and above, and they were pretty mean. I hope I didn't suffocate your web server with generating them!

How fast is the solving algorithm, and how does it compare to that in the original paper which inspired you, and how quickly can it (your own algorithm) solve f.ex the typical level 100's on a given system?

No problem. =)

The solution is a bi-product of the puzzle generation algorithm, so it would take no additional time.

Reverberations

lft
Linus Åkesson
Tue 16-Sep-2008 22:04
I'm assuming this uses modern equal temperament? [half step up = x * 2^(1/12) ]

You should experiment with some temperaments that were popular during Bach's time.

-Andy

That's an excellent suggestion. Thanks!
lft
Linus Åkesson
Tue 16-Sep-2008 22:06
This is lovely. Thank you very much for sharing. Of course I too would like to play with the original files, but I'm glad you've seen fit to share even the MP3s. Do we have a license to copy them around as well?

Oops, forgot to sign that — I'm Kragen Javier Sitaker, kragen@canonical.org.

Yes, do copy them around. Sharing is caring.

A case against syntax highlighting

Imperceptus
alexander miglin
Wed 17-Sep-2008 19:23
I honestly think that any development that has stemmed from HTML needs syntax highlighting. I do remember when I didn't have it amidst making websites, I am very thankful that I do now.

Although I would agree that languages like c,c++ or even .net could really do away with them with no loss to the author.

Craft

Anonymous
Fri 19-Sep-2008 15:40
That is a very nice example of lateral thinking making the best of the AVR's potential.

Full marks!

Joey
Anonymous
Fri 19-Sep-2008 18:25
I've played about with generating video directly from an AVR myself, did most of a space invaders game as a demo, and I've actually used similar techniques on commercial designs to drive graphic LCD displays directly from an AVR (the timing is rather less critical with LCD's)... That included driving a windowed display using a Mega128 with next to no external hardware, so from the perspective of someone who knows exactly what's involved let me say that you've done a beautiful job there... Congratulations :)

One man and his piano

Anonymous
Fri 19-Sep-2008 20:58

Eddy-B wrote:

This is one of my favorite Hubbard tunes.

But this version, being quite horrible at times, can't be improved much on i guess using only a piano, other than just fixing the off-key sounds - i don't think the original has any off-key notes.

It was a good try at that but i'd rather listen to the SID instead.

The hardware chiptune project

Anonymous
Sat 20-Sep-2008 05:07
Linus, I'm trying to compile the tracker under mingw32 envirotment... well.. it compiles allright (after getting rid off err() calls, replacing ncurses with pdcurses and adding some os specified libraries for SDL) but nothing happens - not even an error message (i replaced err with printf())
could you provide any help? i'm more assembly coder than c one :(
Anonymous
Sat 20-Sep-2008 07:22
after another two hours i got this to work
instead pdcurses for win32, there is pdcurses for SDL library which works as it should (win32 version needs LINES and COLUMS as system envirotment variables, and works only if run from command prompt)
anyway...
MakeFile:
LDFLAGS=-lpdcurses -lmingw32 -lSDLmain -lSDL -mwindows

main.c:
if(argc != 2) {
fprintf(stderr, "usage: %s <filename>\n", argv[0]);
}
...
if(SDL_OpenAudio(&requested, &obtained) == -1) {
fprintf(stderr, "SDL_OpenAudio");
}

and <err.h> (main.c, gui.c) is no longer needed

hope it will be of some use for someone...

Craft

Anonymous
Sun 21-Sep-2008 21:19
Whats the potentiometer for?
Anonymous
Mon 22-Sep-2008 03:20
Hi, great work. I am trying to rebuild this thing. Whats the PNP transistor? Is "BC560C" okay?
Anonymous
Mon 22-Sep-2008 13:59
Hi, great work. I am trying to rebuild this thing. Whats the PNP transistor? Is "BC560C" okay?
Nevermind, I tried it. It works.

Allt under himmelens fäste

Anonymous
Thu 25-Sep-2008 01:22
Beautiful song, and nicely done in SID!
Kind Regards

Tel B :)

Craft

lft
Linus Åkesson
Fri 26-Sep-2008 18:18
Whats the potentiometer for?

It's for adjusting the intensity of the white high-res overlay used for text, so the text won't bleed (too high) or turn grey (too low). Different transistors have different hFE factors, which also vary with temperature, so it's convenient to be able to fine tune the system after it has been assembled.
Anonymous
Tue 30-Sep-2008 23:04
Very impressive, then I saw the Mandelbrot being calculated in real-time and my mind possibly just exploded :-)