SUGGESTIONS

Super ST Project. Lets create a awesome new ST! Fix all the bugs and add more cool stuff!
User avatar
exxos
Site Admin
Site Admin
Posts: 6856
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: SUGGESTIONS

Post by exxos » Tue Sep 11, 2018 4:22 pm

I used the Falcon RAM boards as they was on evilbay for £5 when I designed the board, they hadn't sold for months, So I used them. Unfortunately they since all vanished and I regret not buying them all. Problem was the STF board was sat idle for many months as I had not had time to work on it. The result is no easy to find RAM cards anymore. Of course is not a good idea "now", but it was 12 months ago.

As said many times, the card will not be used on later revisions anyway. After I have got the FPGA blitter under control, the MMU is next. Wolfgang did a MMU core with SRAM. So the Falcon RAM card will not be used at all then.

I have been talking to wolfgang also about adding a fast block clear function into the MMU. Of course someone will have to code a benchmark routine to compare CPU clear, Blitter clear and MMU clear to see if its faster or not. It should be, the CPU would only have to do 2 or 3 bus cycles to run a block clear in RAM. I'm assuming blitter and CPU would have to clear RAM byte by byte.. which would take up thousands of bus cycles. Of course I am not a expert programmer.. so maybe someone else knows more about how many cycles things take.

We must also think the new MMU can run much faster than the CPU.. with 10ns SRAM, plus FPGA delays, It should be able to clear ram many times faster with such speeds. It may not be much faster with a stock 8MHz system.. it would have to be benchmarked. Though this could be easy adaption for screen clear in games.. and maybe some things in TOS could be patched for faster screen clear with new MMU.

It could be possible to run the whole system at 8MHz, but use for example 100MHz speeds for screen clear. I don't know if that would break raster stuff still with a faster screen clear ?
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

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

troed
Software Moderator
Software Moderator
Posts: 490
Joined: Mon Aug 21, 2017 10:27 pm

Re: SUGGESTIONS

Post by troed » Tue Sep 11, 2018 5:03 pm

exxos wrote:
Tue Sep 11, 2018 4:22 pm
I don't know if that would break raster stuff still with a faster screen clear ?
It would have to be addressed in a new way to not break old code.

User avatar
exxos
Site Admin
Site Admin
Posts: 6856
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: SUGGESTIONS

Post by exxos » Tue Sep 11, 2018 5:05 pm

troed wrote:
Tue Sep 11, 2018 5:03 pm
exxos wrote:
Tue Sep 11, 2018 4:22 pm
I don't know if that would break raster stuff still with a faster screen clear ?
It would have to be addressed in a new way to not break old code.
I can only really think that the CPU will have to write start and end address of block to clear into a register. Then the MMU will clear that block, and likely send DTACK to CPU when clear is finished.
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

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

troed
Software Moderator
Software Moderator
Posts: 490
Joined: Mon Aug 21, 2017 10:27 pm

Re: SUGGESTIONS

Post by troed » Tue Sep 11, 2018 5:28 pm

exxos wrote:
Tue Sep 11, 2018 5:05 pm
I can only really think that the CPU will have to write start and end address of block to clear into a register. Then the MMU will clear that block, and likely send DTACK to CPU when clear is finished.
Exactly. That wouldn't break any existing code (bar any miswrites to that previously not used register of course).

User avatar
exxos
Site Admin
Site Admin
Posts: 6856
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: SUGGESTIONS

Post by exxos » Tue Sep 11, 2018 5:42 pm

troed wrote:
Tue Sep 11, 2018 5:28 pm
Exactly. That wouldn't break any existing code (bar any miswrites to that previously not used register of course).
I guess patched code could check the register to see if a write fails or something.. Then it knows if its running on the new MMU or not... or just separate patched versions of software :shrug:
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

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

troed
Software Moderator
Software Moderator
Posts: 490
Joined: Mon Aug 21, 2017 10:27 pm

Re: SUGGESTIONS

Post by troed » Tue Sep 11, 2018 6:11 pm

exxos wrote:
Tue Sep 11, 2018 5:42 pm
I guess patched code could check the register to see if a write fails or something.. Then it knows if its running on the new MMU or not... or just separate patched versions of software :shrug:
Yeah that's no problem. Demos can easily check to see if the functionality is there, and new TOS images could set cookies.

alienkidmj12
Posts: 32
Joined: Tue Aug 22, 2017 1:39 pm

Re: SUGGESTIONS

Post by alienkidmj12 » Fri Sep 14, 2018 11:44 am

exxos,

you will be down in the hall of fame for someone to reproduced an atari stfm,

it will more than likely be in someones collection in 25 years time, perhaps in a perspex box for viewing purposes only :)

passed down through the generations :) until no one even knows what its for :)

dave

KyleB wrote:
Tue Aug 28, 2018 1:11 am
Been thinking a while about the ram being a falcon board. Not sure that's a good idea, I mean I get the basic principle - all falcs are 14mb these days it seems so why not recycle - but not sure that these 4MB boards are going to be all that plentiful anymore after 25 years of being chucked in the bin.

Is there not some 4MB ramchip that will work in an ST circuit? Or even just one 4mb simm, seems easy enough to find on ebay especially laptop stuff.

stephen_usher
Posts: 286
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
Contact:

Re: SUGGESTIONS

Post by stephen_usher » Thu Oct 04, 2018 8:28 pm

The one thing that the ST hasn't got which would be highly useful would be an expansion port to add peripherals to.

The discussion about the second CPU got me thinking about how you could create a generic expansion system memory mapped into the ST address space. Then occurred to me that we do actually have one, though it's read-only (unless you use tricks) and can't generate an interrupt: the cartridge port.

Of course, the new STF would have to be fully backwards compatible with cartridges but I was wondering what control lines would be needed to be added somehow to give full write functionality and allow it to generate an interrupt. Would it be few enough to use a standard connector and short ribbon cable from an additional externally accessible port?

Of course, one of the great benefits would be that TOS tries to boot from the cartridge, so a ROM could be used by any peripheral it initialise it out of the box, as it were.

I could see it being useful not only for such things as ethernet devices (faster than NetUSBee as it'd have interrupts and not use "write using read" hacks) but possibly reasonably fast USB or other specialist devices. It could open up all sorts of possibilities without having to open the case.

Any thoughts as to whether this might be feasible?
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.

User avatar
rpineau
Site Admin
Site Admin
Posts: 468
Joined: Thu Aug 17, 2017 6:08 pm
Location: USA
Contact:

Re: SUGGESTIONS

Post by rpineau » Thu Oct 04, 2018 8:34 pm

I agree the ST need a proper expansion bus.
I put on ont he 68020 card me and Juliusz are working on. It has all the 68020/30 signals plus router BR/BG and 7 IRQ pins (that runs to the CPLD which will then trigger an level 5 interrupt, which in a MSTE is the same as the SCC and on ST/STE is not used).
And we already have a few extra card in mind (and partially developed) like Ethernet.
May be a subset of this expansion bus could be used on the STFM remake in 24/16 mode instead of the 32/32 mode.
Rodolphe
Working ones : MegaSTE (68020) / TT030 / Falcon with AB040 & Eclipse / 1040STF
Need testing : Falcon with CT2

User avatar
exxos
Site Admin
Site Admin
Posts: 6856
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: SUGGESTIONS

Post by exxos » Thu Oct 04, 2018 8:35 pm

stephen_usher wrote:
Thu Oct 04, 2018 8:28 pm
The one thing that the ST hasn't got which would be highly useful would be an expansion port to add peripherals to.
VERSION 2.

viewtopic.php?f=19&t=71

stephen_usher wrote:
Thu Oct 04, 2018 8:28 pm
I could see it being useful not only for such things as ethernet devices (faster than NetUSBee as it'd have interrupts and not use "write using read" hacks) but possibly reasonably fast USB or other specialist devices. It could open up all sorts of possibilities without having to open the case.
There was already some talk about this last year.. http://atariage.com/forums/topic/267907 ... r-improve/

At some point I have considered reusing one of the 3 gnd connections to route a RW signal to the cartridge port.
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

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

Post Reply