When is a ST not a ST anymore ?

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exxos
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Re: When is a ST not a ST anymore ?

Post by exxos » Sat Jul 14, 2018 10:00 am

Petari is right, only real problems are "undocumented features". But these can always be fixed.

For example Suska shifter core does not know about "wakeup states". So some demos will fail. But now these problems are known and better understood, these can be added into future revisions of the core.

Most instructions if running from 8MHz on real 68000 CPU, will be no problem there. MMU/GLUE will be waiting for CPU to complete cycles, so there would be no speed difference there anyway, not if using real CPU.

As for ACIA, I am not aware of any side-effects of that system running faster. The only time I ever notice a difference was when playing sampled sound and moving the mouse, this would cause the sampled sound to slow down. If the system was running faster, the side-effect would be that slowdown would be a lot less. Which I would actually see as a good thing. So as far as I'm aware 100% emulating that isn't really needed anyway.

Other side effects could be MMU may work faster with DMA transfers, and indeed DMA itself may run faster. But this would be welcome anyway. I don't know of any side-effects of running transfer rates and hard drives faster. Hard drives over past 30 years have various access speeds anyway.

Floppy drive may well be special case because of various protection techniques used the timing of floppy chip.. But in this case and still use real IC anyway. Same for MFP etc. Of course floppies are thing of past and in 30 years time likely no real floppies will work anyway, having 100% floppy emulation would actually be pointless. Will likely nobody will care by the time the 1772 vanishes of the market totally.

We can always look at it like a "cloned ST" will likely be more compatible than the Falcon. We can also look at it like we have no choice but to "emulate" the Atari chips, simply because there is no alternative. Of course once we are in FPGA, we can add more features such as higher RAM speeds, better video resolutions, more colours.. And of course my goal is always 100% backwards compatibility, but sacrificing that 1% incompatibility to gain much more is a good trade I think anyway.

I guess it depends if people think the Falcon is the next "ST" computer or not. People are happy with the Falcon I think as it is still a Atari TOS running computer. And what we are talking about will be more compatible than the Falcon but obviously not as advanced.
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Re: When is a ST not a ST anymore ?

Post by Petari » Sat Jul 14, 2018 11:04 am

Just one small correction: moving mouse causes slowdown, of course. But most of it is not in IKBD, ACIA, not even in interrupts generated - but in drawing and undrawing mouse cursor .
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Re: When is a ST not a ST anymore ?

Post by Darklord » Thu Jul 19, 2018 6:59 pm

I love these threads. I commented earlier but I find other Atari users opinions to be
intriguing.

Especially the part about if you do an upgrade is it no longer an ST?

Short answer, I'd say yes.

I have a Mega ST that runs my BBS. It was originally a 2 meg, TOS v1.02 machine.
Upgraded to 4 megs, TOS v1.04 and an AdSpeed accelerator. Is it still a Mega ST?

You bet it is.

Same goes for my STacy. It was a stock 2 meg version when I got it, with a seriously
degraded screen. Took it to 4 megs, replaced the back-light for the panel, replaced
the dead (and burnt!) 10 meg hard drive with an Ultrasatan, put in a Pak 68/3
accelerator, 1.44 floppy drive upgrade and painted it black (until something darker
comes along :) ).

Is it still a member of the ST family? Is it still a STacy?

Of course it is. :)
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Re: When is a ST not a ST anymore ?

Post by exxos » Thu Jul 19, 2018 7:09 pm

But if your whole STacy circuit was a "one chip wonder" in FPGA, is it still a STacy then ?
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

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Re: When is a ST not a ST anymore ?

Post by Steve » Fri Jul 20, 2018 1:52 am

Yeah I think the thread went a little off-topic when people started to talk about normal upgrades, where as the original question was about FPGA replacements for multiple chips.

It's kind of like cars isn't it? Old-school mechanics hate newer cars because everything is electronic and you can hardly do any servicing yourself and will often require taking it to the dealer. It's the same with my Ataris, if something goes wrong I like how I can find the problem chip etc, replace it and have it working again. Where as if it was entirely an FPGA, if the chip dies, that's it - it is totally dead. Or if something is wrong with the logic, you can't fix it unless you're a wizz programmer, effectively having to wait for the 'car dealer' or people who make the cores to fix the problem.

I think the machine loses it's soul when FPGA comes into it. It is the same with my retro PC. I love 3dfx Glide graphics for my old games, I like to play them on original hardware. It's not the same using a Glide wrapper on a modern system.

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Re: When is a ST not a ST anymore ?

Post by mikro » Fri Jul 20, 2018 8:35 am

Yeah, I guess there's something to that 'analog feeling'. I'd even say that more analog = more attention it gets. It's a very subjective observation but look how many accessories/addons are here for the 8-bits, STs and Falcon. Except the recent CT60e (which I'm hesitant to label as 'new') it's been 15 (!) years since the last Falcon hardware, the SuperVidel, was announced.

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Re: When is a ST not a ST anymore ?

Post by Petari » Fri Jul 20, 2018 8:40 am

I must disagree here. FPGA is just another step in chip manufacturing. It was always the same goal: to put more and more functions in 1 chip.
In case of Atari ST family big leap was to put high integrated GSTMCU with lot of pins on motherboard. Later revisions include blitter too.
Reasoning that in case of failure must replace whole FPGA are not valid. What matters is production cost. Imagine ST with all simple 74xxx logic chips. There would be hundreds of them . Great ! If something breaks, you need only to replace 1 cheap chip ! Wrong - time is money. And you will need plenty of time to find which is broken. Not to mention that machine would cost 5x more, consume 6x more el. power. Size of closet :D

3D Glide wrapper is just translator - what translates modern 3D functions to now removed Glide 'language' . But Glide is actually translator too - it translates GLide commands, functions to low level. chipset specific ones.

'Translation' is the future - actually, it is present already. In both meanings. Some can see it as emulation, but that's different.

The real problem here is that it is not enough to make faithful ST clone now. Because everything is changed - so you need different video output, to get rid of floppies - this later may be new for some people, but will be a must in few years. You can not make everything. Atari self did not make floppy drives. And many components. So, there is a choice: making it 100% compatible - then will need proper momitor, capable to show old type PAL, NTSC freq. video. Or using converter - but then, much better & cheaper is when clone produces self HDMI. Floppy, keyboard, mouse ... nothing ST compatible is manufactured.
So, I would rephrase whole dilemma: What peripherals should we use with our ST clone ?
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Re: When is a ST not a ST anymore ?

Post by Petari » Fri Jul 20, 2018 8:43 am

mikro wrote:
Fri Jul 20, 2018 8:35 am
Yeah, I guess there's something to that 'analog feeling'. I'd even say that more analog = more attention it gets. It's a very subjective observation but look how many accessories/addons are here for the 8-bits, STs and Falcon. Except the recent CT60e (which I'm hesitant to label as 'new') it's been 15 (!) years since the last Falcon hardware, the SuperVidel, was announced.
Yes, it is very subjective. And there are oldies with much more add ons available. Maybe to leave all this digital crap computers and making Edison type phonograph - I always liked that concept - not some dumb disk, where data density varies as needle goes toward center. Cylinder is ideal for audio storage !
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Re: When is a ST not a ST anymore ?

Post by exxos » Fri Jul 20, 2018 8:49 am

Petari wrote:
Fri Jul 20, 2018 8:40 am
So, I would rephrase whole dilemma: What peripherals should we use with our ST clone ?
That is valid point actually..

I mean some want to use PC keyboard USB etc If not using the ST keyboard, then it lessens the ST's identity.

As mentioned before though, several brands of PSU... my PSU's are of course not original, but mine is just "another brand" of PSU. So there is no real "true ST" design anyway.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

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Re: When is a ST not a ST anymore ?

Post by Petari » Fri Jul 20, 2018 9:20 am

PSU is straight case. Give proper voltages and enough current, with stability and low noise.
But something like keyboard is not it - some PC keyboard uses different codes, different commands, probably even different serial protocol. So, needs to be translated, to make some HW adapter. What is actually done already - Eiffel. Or in case of mouse - Pest + some other PS2-Atari converters.
Actually, we have all it already. But video conversion is something more relevant, and converters are not cheap. + quality may be not best.
So, I think that video is most problematic part here. Ideal solution would be to have both: analog RGB (no need now for PAL/NTSC color encoding) + HDMI output . And that's actually not problem to make - since best is to leave video generation to original frequencies - that will ensure SW compatibility. And doing converter to HDMI or DVI, so ~30 KHz, 60 Hz digital signal with extra HW, what will not use analog RGB out, but digital outputs from shifter - as I talked about it in another thread. That will give much better quality than external converters, with lower price.
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