log in | register | forums
Show:
Go:
Forums
Username:

Password:

User accounts
Register new account
Forgot password
Forum stats
List of members
Search the forums

Advanced search
Recent discussions
- South-West Show 2019 talks (News:)
- South-West Show 2019 in Pictures (News:)
- South-West Show 2019 Report (News:3)
- AMCS free versions are live! (Gen:14)
- Code GCC produces that makes you cry #12684 (Prog:33)
- Show West Show 2019 preview (News:1)
- January News (News:3)
- Armx6 Not booting (Gen:7)
- RISC OS on youtube (News:)
- The environmental cost of software (Prog:7)
Latest postings RSS Feeds
RSS 2.0 | 1.0 | 0.9
Atom 0.3
Misc RDF | CDF
Site Search
 
Article archives
The Icon Bar: General: Simtec Turbo RAM Upgrade
 
  Simtec Turbo RAM Upgrade
  Charlie (18:38 12/2/2010)
  vanpeebles (23:49 12/2/2010)
  nunfetishist (00:06 13/2/2010)
    vanpeebles (10:09 13/2/2010)
      nunfetishist (15:46 13/2/2010)
        bhtooefr (16:01 13/2/2010)
          nunfetishist (19:12 13/2/2010)
            bhtooefr (20:33 13/2/2010)
              nunfetishist (01:03 14/2/2010)
                bhtooefr (02:10 14/2/2010)
        Charlie (17:22 13/2/2010)
          vanpeebles (23:36 13/2/2010)
            Charlie (23:46 19/2/2010)
              vanpeebles (12:35 20/2/2010)
              asm1 (19:49 26/4/2010)
                Charlie (22:50 28/4/2010)
 
Charlie Message #113343, posted by Charlie at 18:38, 12/2/2010
Member
Posts: 95
Another topic got my juices flowing with regard to this seemingly v. rare upgrade.

I'd be most interested in redeveloping it as a home-brew project for personal interest and also so I could write a 'how-to' for others to follow.

A request:
Does anyone have one of these and would be prepared to lend it to me for examination?

Thanks
  ^[ Log in to reply ]
 
vanpeebles Message #113353, posted by vanpeebles at 23:49, 12/2/2010, in reply to message #113343
Member
Posts: 198
A worthy cause, I can't even find a picture on the net. Do you think it was a standard 4mb upgrade just fitted with a higher speed memory chip or was it more involved than that?
  ^[ Log in to reply ]
 
Rob Kendrick Message #113354, posted by nunfetishist at 00:06, 13/2/2010, in reply to message #113343
nunfetishist
Exposing morons since 1981

Posts: 488
Do you have any more information on this at all? I've never heard of it. What machine was it for? What size of upgrade was it? What was the nature of the "turbo" ?
  ^[ Log in to reply ]
 
vanpeebles Message #113356, posted by vanpeebles at 10:09, 13/2/2010, in reply to message #113354
Member
Posts: 198
From what I remember it was a 4mb upgrade for the A3010 that also gave it a speed boost. I think it was claimed to be an extra couple of mips.

They weren't around for a long time because Simtec had troubles getting their hands on the higher quality ram that was needed.
  ^[ Log in to reply ]
 
Rob Kendrick Message #113364, posted by nunfetishist at 15:46, 13/2/2010, in reply to message #113356
nunfetishist
Exposing morons since 1981

Posts: 488
Right, here we go. The 'Turbo RAM' upgrade was a 4MB upgrade that used some stupidly-fast 40-50ns 4Mbit FPM memory (8x 1Mx4). Usually, upgrades at the time used 70/80ns. The upgrade also replaced the memory system clock of the ARM250 to clock the memory at higher speeds. The default 36MHz clock was replaced with a 40, 42, 44.5, 48, 50, 55, 60 or 64MHz part, depending on on quick it went and then backing off a bit, and then tested with elevated temperatures to check it still worked.

The upgrade would not work if the machine had a mezzanine board (ARM2+VIDC+IOMD+IOC on a PCB instead of the ARM250), but it is possible to upgrade it to an ARM3.

Somewhere there is a PDF with installation instructions. I'll see if I can dig that out.

The parts to do this upgrade are staggeringly difficult to find now, so it is unlikely to be reproducible.
  ^[ Log in to reply ]
 
Eric Rucker Message #113365, posted by bhtooefr at 16:01, 13/2/2010, in reply to message #113364
Member
Posts: 337
Well, it's not THAT hard to find 50 ns FPM DRAM - Digikey has it as a non-stock item, but minimum order of 80 for SOJ or 117 for TSOP for 50 ns 1Mx16 - two of those per board. They're about US$5-6 a piece at those quantities.
  ^[ Log in to reply ]
 
Charlie Message #113368, posted by Charlie at 17:22, 13/2/2010, in reply to message #113364
Member
Posts: 95
Thanks very much for the info, I appreciate it.

Please, if you have any further info I'd be grateful.

The tricky bit is driving 'memory' and 'CPU' faster without affecting I/O.
Either this isn't an issue with ARM250-based computers (unlike all the others) or it's like the A3000 turbo upgrade that uses software to slow the system to normal when I/O like FDD is accessed...
...the more I know the easier it will be to reproduce - I'm no expert @ this kind of thing, an interested amateur.

Also
To my limited knowledge this was an A3010-only upgrade, why not the A3020 or A4000..?
  ^[ Log in to reply ]
 
Rob Kendrick Message #113369, posted by nunfetishist at 19:12, 13/2/2010, in reply to message #113365
nunfetishist
Exposing morons since 1981

Posts: 488
Well, it's not THAT hard to find 50 ns FPM DRAM - Digikey has it as a non-stock item, but minimum order of 80 for SOJ or 117 for TSOP for 50 ns 1Mx16 - two of those per board. They're about US$5-6 a piece at those quantities.
Found the right type of crystals yet? >smile
  ^[ Log in to reply ]
 
Eric Rucker Message #113370, posted by bhtooefr at 20:33, 13/2/2010, in reply to message #113369
Member
Posts: 337
Digikey has 209 different 40 MHz, one 42 MHz (although obsolete, and possibly unavailable,) three different 44.545 MHz, 143 different 48 MHz, 60 different 50 MHz, six different 55 MHz, 25 different 60 MHz, and 27 different 64 MHz.

Admittedly, some of those items are duplicates - the same part is listed twice for a reel of SMD parts and for an individual part cut from that reel.
  ^[ Log in to reply ]
 
vanpeebles Message #113375, posted by vanpeebles at 23:36, 13/2/2010, in reply to message #113368
Member
Posts: 198
If you can make something similar then you have a sale right here!
  ^[ Log in to reply ]
 
Rob Kendrick Message #113376, posted by nunfetishist at 01:03, 14/2/2010, in reply to message #113370
nunfetishist
Exposing morons since 1981

Posts: 488
And how many of these crystals are the right voltage and pin-out? I'm imagining vanishingly few.

Sorry, but it's less effort to buy a second-hand RiscPC.
  ^[ Log in to reply ]
 
Eric Rucker Message #113377, posted by bhtooefr at 02:10, 14/2/2010, in reply to message #113376
Member
Posts: 337
I didn't check that, although pinout problems can be worked around. wink

But, it'd make more sense to buy a cheap Atom PC and put RPCEmu on it. wink
  ^[ Log in to reply ]
 
Charlie Message #113453, posted by Charlie at 23:46, 19/2/2010, in reply to message #113375
Member
Posts: 95
If you can make something similar then you have a sale right here!
If I can remake one of these the idea is to put the schematics up for all to play...
...I don't (currently) own an A3010 so if anything comes of this plan I'll gladly send you the first prototype in exchange for some testing.


Why? I like fiddling with old-ish computers...
...anyone want to know how to split the A5000 'Fast VIDC' and MEMC clocks?
It's easy and allows more over-clocking options. smile
  ^[ Log in to reply ]
 
vanpeebles Message #113456, posted by vanpeebles at 12:35, 20/2/2010, in reply to message #113453
Member
Posts: 198
I hope it does, would be great to get my hands on something similar after all these years!
  ^[ Log in to reply ]
 
Andrew Message #114145, posted by asm1 at 19:49, 26/4/2010, in reply to message #113453
Member
Posts: 122
Charlie

You know I will be your best friend forever if you put me at no 2 on your prototype testers list big grin

For those who don't know. I got the last Super turbo board from simtec back in the day.... as usual, stupidly sold the machine when moved to PC.... /cry /swear etc.

cheers

Andrew
  ^[ Log in to reply ]
 
Charlie Message #114167, posted by Charlie at 22:50, 28/4/2010, in reply to message #114145
Member
Posts: 95
Hello,
I may have some rather good news:

Tom Walker's worked out how to overclock his A4000 - and so probably the A3020. The A3010 is a bit different...

...Having had a proper look @ the A3010 schematics it looks like doing something equivalent to the Simtec Turbo upgrade will be really easy, but:
-I've yet to get my hands on an A3010 to test it.
-I doubt it will work unless there's a 4mb upgrade fitted (motherboard RAM is probably too slow)
-Even with a 4mb upgrade stability may be an issue.

but:
-If the above won't fly for most peeps I have a (somewhat more complicated) plan which won't overclock things quite so much.

As soon as I've had a chance to give it a go I'll report back.

Fingers crossed...
  ^[ Log in to reply ]
 

The Icon Bar: General: Simtec Turbo RAM Upgrade