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An interesting interview from flashback
"Stephen Leary was our honored guest here in Flashback-Computing"
source :

Stephen Leary, also known as TerribleFire in the retro community is the man and the brain behind the open source accelerator boards for the Amiga and Atari home computers.
A kind soul where he shares his knowledge with all of us, by giving the schematics and code of his work!
While listening some mods on EaglePlayer, we had a conversation about his projects.
He kindly shared his time with me for an interview about himself and his efforts.

Sit back and relax, here we go.

Flashback: So, tell us a few things about you.

TerribleFire: I am Stephen. I am a software engineer from Glasgow. I studied Electronics & Electrical Engineering here in Glasgow. I love to fly aeroplanes, go running and play with retro computers.

Flashback: Aeroplanes!!! That's fantastic!
When was your first touch with computers?

TerribleFire: Probably aged 5 when the BBC Micro appeared at our local school. I remember seeing it but we weren’t allowed to use it unattended. I got a Spectrum when I was 7 and started programming then.

Flashback: So later after coding, did you start making hardware and if you did what was it?

TerribleFire: I had to make all sorts of hardware for my degree. But most of them either had embedded processors or were analog devices like amplifiers etc. Then a few years ago (2011) I bought myself a Digilent Atlys and stared developing FPGA models in verilog. I ported Mike Stirling's BBC FPGA to verilog and made an Atari ST model. Eventually I produced the Archimedes model for the MiST board.

Flashback: That is quite a large work you did.
What about your present projects. What you're fighting with these days.

TerribleFire: The TF520 accelerator board was a proof of concept board for the Amiga that I have wanted to make for years. It was mostly designed to see if I could make things work using the Xilinx CPLDs. Then we moved a board that people might want… the TF530. Now that that is done some more experiments will follow before we get to CD32/1200 boards. I love all 68K machines so I will also make things work on the Atari ST too. But that upsets some people.

Flashback: If I understood well, people are getting upset for supporting the ST series?
As a hardcore Amiga fan I think this is ridiculous, we need hardware for every machine out there.
Are you going to a superscalar approach in near future like 040/060 CPUs?
And how about FPGA based accelerators like the Vampire; do you have something similar in mind?

TerribleFire: I think there are some silly fanboys out there still... many of them have mental issues!!!!
I think eventually I will do an FPGA card for one of the machines... Probably after I do a TF1230 board. I dont know which machine it will be for first... Probably the CD32 because it’s the smallest on my desk!!!! I will work with Till Harbum and Chris (Exxosuk) to figure out how to get this all done right. But that is later down the line... much later.

Flashback: Well you can't make everyone happy right?
Many people ask if it is possible to use software emulation on an accelerator card equipped with an x86 CPU?
This would be the fastest thing on earth.

TerribleFire: Indeed. Some people will always be upset.
I have sometimes thought and discussed with people this idea to use an emulator card.. The x86 has high latency so the "feel" would be the same as winuae. However a fast ARM processor might make sense. I have had some ideas of using an ARM processor in the same way some cards use PPCs. Much much later though! :)

Flashback: I have a PPC card on my A1200 and the CPU is utilized more like an FPU "I will call for help" and this is not the best approach unlike the OS4 which goes direct to it.
Will be a different approach like emulation or we'll need specific software/OS to use it?

TerribleFire: I am thinking it might be more like a graphics co-processor really. Except the ARM is way better for this sort of thing than a PPC. An opengl graphics accelerator is what i'm thinking.

Flashback: So we will need new software for it.
The Amiga scene is producing hardware but it lacks software releases.
Do you think the cause of this is the difficulty to code so many co-processors unlike more simple CPU based machines?

TerribleFire: Probably. But also availability of the cards. I couldnt get hold of a PPC amiga for less than £500.
I think if we had a better abstraction layer it would work better... but is often hard to get the API documentation or it doesn’t work as expected.

Flashback: Are there any benefits on the ST with your boards, will make some progs run faster?
And as for the games, will 3D games have benefit from this and how about 2D games.
Will they maintain their original speed or just will go bananas and how about frame skipping? Will be the animation smoother?
Any compatibility issues?

As for the Amiga versions (spoiled brat mode on ;-)
We need more RAM!!!

TerribleFire: So keep in mind that the TF520 was my first accelerator… From there I went to a very complicated board in the TF530. I really wanted to make a board that could be built really cheap and that meant getting it into 10cm x 10cm. This is because at that size it is $2.50 for the PCB (including delivery). That’s an amazing price. Unfortunately I couldn't find a way to make more RAM fit on that size of board and I wanted to keep that part simple this time round. When you consider that we have 030, FPU, 2Mb of RAM, IDE and potentially SPI support on a board that is smaller than the Kipper2K ram card… it’s pretty amazing I think.

More RAM is something I will think about.

Flashback: Why TerribleFire and why for free?
I have seen other people contributing things for free to the community like Mr.Petari and always getting a hard time from others.
What would be the profit for your time - knowledge and money spent for parts?
Will people's gratitude warm your heart and be your payment?

TerribleFire: TerribleFire is a sort of "nickname" I have been given by my best man. Some things have gone on fire in the past... :)
I don’t understand why people give others a hard time. Chris (exxosuk) and I have both been slammed on the forums lately for not "getting behind" Vampire. My only issue with Vampire is that I could do a lot of work there, still make no money, and everything would still be closed source.

I enjoy making the boards and I would probably make them anyways. If nobody is interested in them I would just stop making videos and publishing. I'll make the boards anyway... If people want to watch and get excited about new hardware then I am happy for that... I know that people in the Acorn/Archimedes space would love me to be making boards for those machines or working more on the FPGA model.

Flashback: Every scene needs attention and although I am not an Archie owner (hope to be in the near future) I would love to know that there is good hardware waiting for me.
The million dollar question:
Which computer would take with you in a deserted island/heaven/hell etc...?

TerribleFire: Very difficult question. Probably a Spectrum +3. Amiga close second.

Flashback: Almost a wise choice :-D
I am not a hardware guy at your level, so is there anything else to add?
Technical details, a message, anything!

TerribleFire: Just that the more people are interested the more work I will do on the boards. Happy retro-ing everyone!

Flashback: From the bottom of my heart, I thank you for your time making this conversation with me and your efforts to the community.

YouTube Channel

GitHub resources

EAB Chat
Software / Improving Atari ST Uridium
« Last post by Petari on 03-03-2017, 22:11:56 »
ST version of Uridium is known as slow and not well playable. Usually people blaming lack of HW scroll support for that. But scrolling self is actually not that bad. What is very bad is slow ship control - it accelerates poorly, turning 180 degrees takes too much time, so hard to play, if possible at all to finish some levels.
I went in improving it. Better scrolling is done by help of blitter. Faster controls needed lot of tracing, code examining.

2 test versions available.
One is for STE, Mega STE. Mega ST, or any ST with blitter. 512KB RAM is enough. Can run from floppy or hard drive.
Selectable start level, so you can try all them quickly.

Other version is with original scroll, just controls are improved - so any ST, STE ... 512K RAM is enough.
Please test it as much can. Feedback is welcome.

This is not final version - I need yet to update sprite draw code in blitter version - because now using whole screen width.
Your Manta performs a 90 degree roll if you press and hold fire whilst moving up or down. This will enable you to manoeuvre through restricted spaces.
Level maps included. - Blitter v. on YouTube. - Original scroll v. on YT.
Software / Re: Prince of Persia with improved sound
« Last post by ataricrypt on 23-02-2017, 00:27:38 »
Absolutely. Amazing. Great work mate. Thank you :-)
Software / Prince of Persia with improved sound
« Last post by Petari on 22-02-2017, 19:10:15 »
Floppy v. :

Some people may be interested about how to replace sound playback in Atari ST games to STE DMA system, like in this case, or in Dungeon Master.
It was pretty much different, although playback code self is almost 100%. First thing is to get quality samples somewhere, somehow. In case of DM there is lot of it available, so quality effect samples too. Also SW for extracting all elementary files - with what I could extract all samples of ST version with descriptive file names. ST version uses 21 samples for effects, while PC version 35. So, needed to listen all it and take proper 21. Then convert them to STE DMAA compatible format. Original ST samples are very compact, all together 17KB. Converted ones 112KB - at relative low samplerate of 12500 Hz. That means of course that RAM requirement is min 1MB - no space for extra 90KB in 512KB. But that is certainly not problem - most of STEs have so much at least. Finding playback code and replacing with DMA one was not hard in case of DM. Then needed to find proper RAM area for samples, code, tables, and that was basically all what I needed to do.  Chaos Strikes Back uses same samples as DM, so it was really not big work to solve it too.
Prince of Persia was harder, mostly because there was music playback too, + I needed to fix some bugs in it's code, which I encountered during tests.
But I dealt already with it some years ago, when disassembled it completely and made some fixes for working on higher TOS versions, Falcon.  That was big help for audio mod. Much less sources for POP than DM online. I just did not see enough good music files. Samples were not separated, so I would need lot of time to extract all from unknown structures.  Fortunately, what was in ST version was good enough quality for STE playback - samplerate was 7680 Hz - pretty high for YM sample playback (that's why game slows a lot during sound effects). So, I only converted them to 12517 Hz STE format, recalculated some tables, replaced playback code, and effects worked like charm. With music was harder, because it was mixed sample and YM generated playback, and there is lot of it - 18 tunes, some with longer duration of some 30 secs. Replacing all it with DMA samples would need lot of RAM or direct hard disk read by playback. Later may be done one day - if I find some really good music. I ripped 4 shorter tunes only from Android v. POP Classic - and that takes some 110KB. So, there is much less music than in ST original, but what matters is gameplay. And all that fits in 1MB. 
I don't think that there is some rule how to do it. Each game is different coded, samples have diverse formats, sources are different ... So all it is: examine, think, look around, acquire, convert, trace, test ....
Software / Dungeon Master and Chaos Strikes Back with improved sound
« Last post by Petari on 14-02-2017, 20:47:12 »

Using STE DMA audio, so works only on STE, Mega STE, TT and Falcon.
Software / Re: Bug Report on Stormtrooper
« Last post by seblalisse on 12-02-2017, 18:17:01 »

Thanks you for both.

Have a nice sunday.
Software / Re: Bug Report on Stormtrooper
« Last post by Petari on 31-01-2017, 21:56:10 »
Thanx for reporting problem.
I fixed it - was pretty much troublesome. At usual place. Did Teenage Queen too. Have fun  :)
Software / Bug Report on Stormtrooper
« Last post by seblalisse on 19-01-2017, 10:04:22 »


I tried Stormtrooper and i have a problem after the game ends when i write my name in the hall of fame. Just after pushing the return button the screen turns blue with big numbers on.

The game blocks here and i must reboot if i want to play again.

I play on a 1040 Ste with satan card.

Software / Teenage Queen request
« Last post by seblalisse on 19-01-2017, 09:00:53 »


Thanks for the games you converted, and what about this great poker game Teenage Queen from Ere Informatique or Exxos, i can't remember.

That was a really nice game with wonderful pictures.

Have a good day.
General chat / Re: Merry Christmas !
« Last post by Anemos on 27-12-2016, 15:58:52 »
Best wishes to all Atarian,s and special thanks to petari
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