Looking for binary data for ST desktop (screen dump)

[atariry]

I have done a search to try to find some binary screen dump data, but didn't find anything. I suspect that there is an Atari ST image format, but I do not know what it is called.

 

For fun I am using a homebrew FPGA board to implement the 3 Atari ST video modes. I currently have hi-res mono mode displaying on a VGA monitor, but the data is random (from an uninitialised 32k memory).

 

I would like to obtain a 32k byte raw binary dump, for the ST desktop, for each of the 3 resolutions. I will use this data to confirm that I am reading the data from the memory and displaying it correctly. I would like to use the binary data to initialise the memory.

 

Note: I do not have an ST (but I am hoping to implement one on a breadboard using a real 68000 and an FPGA for the video and support chips). I also have not installed a ST emulator, so there may be a way to dump the raw binary screen data from an emulator. Recommendations of which emulator to use (perhaps one which incorporates a debugger?) for Win10, and instructions on how most simply to dump the screen memory, would be appreciated. For example is there a key combo to do a screen capture to file?

 

I did have an Atari 1040ST and mono monitor back in the 80's, but sold it in the early 90's. I am now keen to experiment again, and I would like to play with EMUTOS, using hardware built on a set of plug in breadboards. I already have a 68008 with 1Mbyte of memory and an FPGA implementing UART I/O and timer running monitor code I found on the web. I intend to use the homebrew FPGA board to implement the 3 video modes. There is lots to do, but it will be fun getting there, and I hope then to play with old favourite software such as GFA Basic.

 

Thanks in advance...

 

--Atary

[ParanoidLittleMan]

First thing:  in case of ST video modes you have bitmap data, what is exactly 32000 bytes, for all 3 resolutions.

Then have palette. It is 16x2 bytes for low res, 4x2 bytes for medium res, and 1 bit for high res . But normally it is always 32 bytes.

Recommended is to use some common Atari ST picture file format. Mist popular is Degas PIX - PI1, PI2, PI3 .

32034 bytes. First word is resolution, then 32 bytes for palette, and rest is bitmap data as is in RAM .

Yes, I wrote this, but really, all it is online and would be better to perform some search online before asking about basic facts about some popular computer.

Emulator you need is Steem Debugger. You can dump memory sections and even color palette with it. Instructions ? You will figure out it in 5 minutes. GUI rulez !  ?

And you need to read some DOCs about Atari ST HW - like where the video RAM starts, system variables.

 

 

[Cyprian]

12 hours ago, atariry said:

I have done a search to try to find some binary screen dump data, but didn't find anything. I suspect that there is an Atari ST image format, but I do not know what it is called. 

 

For fun I am using a homebrew FPGA board to implement the 3 Atari ST video modes. I currently have hi-res mono mode displaying on a VGA monitor, but the data is random (from an uninitialised 32k memory).

do you need binary files? I can post it later or you can just search for Degas files - Pi1, Pi2 and Pi3. Cut the header (there is a video mode identification and palette registers dump) and the rest 32000 bytes are plain ST screen memory dump.

 

regarding FPGA, that's sound good. Do you have any details? Which fpga, further plans?

[atariry]

Hi @Cyprian_K, thank you for your reply.

 

Ideally I would have liked raw binary files, as this data can simply be loaded into a ROM on the FPGA, but now that I am aware of Degas files, I will be able to extract the binary portion as you describe. I did a quick google and immediately found many of the "pi" format files. See my other reply, but I am not familiar with Atari screen capture formats, and never was.

 

I am using a cheap Altera Cyclone II FPGA. I have created a custom PCB and had some manufactured (at a very low cost) by JLCPCB in China. The board incorporates 5V to 3.3V level translators, a VGA connector, and a fast (12ns) 128k byte Static RAM for video memory. With the extra video memory I intend to implement Atari ST like enhanced video formats, either more colours or resolution, which I understand EMUTOS can support. I intend to implement an Atari like architecture, initially with a 68000, but then upgrading to a 68020 and 68030 (just for the hell of it).

 

I would be happy to post some progress pictures to the ST part of this forum, on the assumption that someone somewhere might be interested!

 

regards...

 

-Atary

[atariry]

Hi @ParanoidLittleMan, firstly thank you for the first part of your reply. This was very helpful. ✔️

 

However, your reply "but really, all it is online and would be better to perform some search online before asking about basic facts about some popular computer", upset me and offended me. Isn't the whole point of a forum about helping people whatever their level of knowledge? Firstly I was an Atari ST owner for many years, and I knew a lot about the computer, more than you might imagine. My interest was hardware related projects and software, such as drivers, to support it. I had no interest in picture formats or drawing software at that time, so Degas file format is news to me. What might be obvious to you, might not be obvious to everyone else? And yes I did several web searches before posting my request, but clearly I suck at putting the right terms into google!

 

I saw something similar in a FPGA forum (probably Intel/Altera) while searching for an answer to an error message. Someone had asked something which Altera FPGA experts might consider "basic FPGA knowledge". One poster replied telling the original poster that they were lazy/stupid/incompetant/etc. but didn't give an answer. Thankfully someone else posted the simple answer. Although I have been using Altera FPGAs for years, I didn't know the answer, so was grateful for the new knowledge. Turns out the answer was found in one paragraph on one page in one of many many Altera PDF documents.

 

regards...

 

--Atary

 

[ParanoidLittleMan]

You have time to get offended, to write longer blah about how your knowledge is high, etc . It may be true. But saying that not good with making proper searches - that's pathetic. If you are not good in it then practice it. Everyone can learn and getting better.

And to add: I did not write anything offending. What I said stays in rules of most forums:  use search instead asking about basic and frequently asked questions.

 

I'm most active in this forum at moment. I gave lot of help to diverse people. And I will do it in future. When they ask something what is not so easy to find, google.

Ah, try with something like: atari st video modes .  atari st video modes specs ...

I made recently page: http://atari.8bitchip.info/astbegfaq.html

That may need much more to add on ... Only if I had some feedback, suggestions.

 

How it was with me and ST in 80-es ? I bought book - that was some 50-60 DEM. Now you can find it, and many other books for free online. I bought diverse magazines. And I was able to solve practically everything, without Internet, forums, or even without using telephone. Some BBS-es appeared, but that was used mostly to DL SW.

[Cyprian]

Attached you can find binary (PAL - palette; BIN - data) files for all three resolutions.

PI1/2/3 files you can open with online tool:

http://recoil.sourceforge.net/web.html

ST_DMP.zip

[atariry]

Thanks again to the two posters for pointing out that Degas format contains the binary raw image with header attached, I was able to find some sample hi-res images and convert them to the FPGA ROM file format. It helped find some bugs in my code, and after quite a few hours of work I am able to display some data from a hi-res screen image. There are still bugs to fix, and I also need to also implement the medium and low res. In the picture attached the red lines are to help me see where the edges of the screen are, while the code is being developed. BTW the photo of the monitor is cropped. The FPGA only has a small amount of memory to implement a ROM, and 8k bytes was all that was available (quarter of a screen), to store the sample image.

 

Also @Cyprian_K many thanks for the actual desktop images. I will use these files to help implement the other resolutions. ?

 

BTW, I was searching for "Atari ST screen capture" and not finding much, whereas I can now see that I should have tried "Atari ST picture formats". My bad!

[Christos]

16 hours ago, atariry said:

Isn't the whole point of a forum about helping people whatever their level of knowledge? Firstly I was an Atari ST owner for many years, and I knew a lot about the computer, more than you might imagine. My interest was hardware related projects and software, such as drivers, to support it. I had no interest in picture formats or drawing software at that time, so Degas file format is news to me. What might be obvious to you, might not be obvious to everyone else? And yes I did several web searches before posting my request, but clearly I suck at putting the right terms into google!

 

Yes, you are absolutely right. You shouldn't have to search every time you need a little thing, and you don't always find the exact thing you need. Sometimes like you say, it's hidden inside somewhere and what is obvious to some, is not to everyone. It all comes down to whether people want to help or not. 

 

Anyway, please keep us updated on your project and don't be afraid to ask. Someone will surely answer.

[ParanoidLittleMan]

This talk about helpfulness is really misplaced this years, in this forum. And in many others. Lot of it remained unanswered.  Then, there is saying: if you really want to help people against starving give them tools for making food instead food.   And what happened here ? I gave perfect tool to atariry - Steem Debugger - and that went ignored. Afraid that will have problems with using it ? Sure, it's done to be used hard ? ... Then, my old friend Christos found reason to say something here - it was "so" helpful. What about spending time and answer to concrete questions instead talking about what is obvious ? For me pretense is obvious. And I had here some really strange experiences with some people - they did not like my answers, and wanted to not use unknown terms for them ? , or something even weirder. I'm not saying that this is case here, but real time consuming thing is not to write or read about something, but to really understand it. And I mean understand, not just to be able to repeat definition, explanation. This is not some skool exam, this is real life ?

 

Now something what will be really useful: monochrome mode is easy. 1 bit = 1 pixel.   Low res. will be much harder. There are bitplanes. Done different than usual.

Tip for googling:   atari st low resolution bit planes

In my opinion, best would be to make some experiments with editing binary data for small part of screen, then watching effect of it on display (screen output). Maybe to play little with program Degas . Yes, that's another reason why to get that emulator.

 

[atariry]

My final post in this thread.

 

Thanks to the binary datafiles generated by @Cyprian_K, I have now successfully implemented medium resolution. It is very useful working with the desktop, because it has a familiar look, and has some interesting data alignments. The red pixels were added manually to the screen binary to to help checking for blanking alignment. I have now connected up the FPGA board to a MC68000 and 1Mbyte of memory using several plug-in breadboards and a lot of wires. I am now writing the code to allow the 68000 to write and read the video memory. This is curently broken, but it will be working soon.

 

This is part of my Atari ST "clone" project which will run EMUTOS. I'm not sure if this is on-topic for this forum, so I will check other posts to decide whether I should post updates at a later date.

 

--Atary

 

 

Edited July 31, 2019 by atariry
typo

[Christos]

Nice! Glad to see it running emutos too. Did you try to run any programs? 

[ParanoidLittleMan]

This IS on topic thread in this forum, for sure. People is interested for Atari clones.

But I must be again "negative" - I mean talking about seemingly bad things, while all what I want is to point on expectable very hard task, some things which may help in this very complex project.

Must laugh on Christos's question - running some program needs much more features, HW implemented.

First to say that we have already very far developed FPGA clones of Atari ST, STE . MIST . There is work on cycle accurate 68000 CPU implementation in FPGA, and ijor is one who working on it, although I did not see him here over some months. There is Mister - some kind of Mist "clone" too.  What is most interesting is that all they use not separated, real 68000 CPU, but it is on FPGA .

To reach point, where can run some SW, program from disk, disk image there is lot of it to do:  maybe hardest part is right CPU emulation, but having real 68000 is not bad idea too. 68008 IS bad idea. That will be never ST clone.  FPGA implementation has advantages - in price, can be run at different clock rates, so at 16 MHz for instance (as it is by MIST) .

Floppy emulation is complex task too - FDC chip is some kind of processor too. Then comes DMA chip, keyboard, mouse etc .

I don't think that single person can do it all in less than couple years. Only if using some open source solutions. Atari ST is very complex machine.

EmuTOS as target ? Well, if you want OS what don't care  for compatibility with lot of very good and popular Atari ST SW, then go on with it.

And for end, there is people who want to make FPGA clones of different Atari ST chips - mostly because it is hard now to find them, and prices go up. I don't know what is made really. Maybe to visit exxos forum ?

 

[Cyprian]

On 7/31/2019 at 2:35 PM, atariry said:

My final post in this thread.

[...]

 

This is part of my Atari ST "clone" project which will run EMUTOS. I'm not sure if this is on-topic for this forum, so I will check other posts to decide whether I should post updates at a later date. 

keep finger crossed and rethink you decision because would be cool to track your progress.