Low-cost A600 acceleration theory

[Matt_H]

With the 500, 1000, and 2000 you could pop out the 68000 and replace it with a 68010 or faster 68000. No need for any other hardware (I think).

Would it be possible to clip a 68000/20 over the one on the 600 motherboard in the usual reverse-socket manner without the need for modification? I'm looking at the MC68HC000FN20. $8.21 for the chip, let's say $10(?) for a socket. $20 for a 2 MIPS (so claimed by Motorola) upgrade isn't bad... provided this theory actually works.

But then there's still the limited memory problem... Sigh.

[iamaboringperson]

[color=993399]D[/color][/b]ude,

just ploping a new 68000 in the socket will have no speed gain whatso ever, since the clock speed is the same
and with a 68010, you would be lucky to get a 0.05% gain in performance

the 68020 has a different pinout and wider buses, and therefore will not work without alot of extra circuitry

my advice is to buy another computer...

[KennyR]

A Viper630 accelerator clips over the 68000 on a CPU and supplies 030/50 speed plus extra memory. Dunno if they still sell them though. I was considering getting the 620 with 020/25 in 1995, but I plumped for an A1200 instead.

[CodeSmith]

iamaboringperson wrote:
[color=993399]D[/color][/b]ude,

Anyone else notice an echo?  :-P

[PPC]

you clould replace the 68000 for an 68010 if can solder SMD, but the only difference is that the 68010 has an FPU and the 68000 does not, so if you want to get some preformance gain you will also have to overclock the proc by using another crystal.

hmmmm buy an A1200 with 040 or 060 card or a 040/60+ppc.
I got myself a blizz ppc 3,5 year ago never regret it, PPC roxXx!

[Cymric]

Wrong, the 68010 does not have an FPU. On-chip FPUs arrived with the 68040; 68030 and lower have to use external chips. The only difference between the 68010 and 68000 is that the former has a special 2-byte instruction cache for very small loops; plus it handles exceptions a bit better, putting more useful information on the stack. It is not worth your money going for a 68010 under any circumstances.

[Agafaster]

Although that 68000 sounds intriguing...

I presume that it runs at up to 20 MHz ?

I'd get hold of a couple of data sheets if I were you:
one for the 68k already in the 600, and another for the one you are interested in.

if they have the same package, and the pinouts are the same, you might want to replace the old one. (SME so very tricky unless you do this for a living !)

you will also need to change the clock crystal on the a600 mainboard (try to get a multiple of the one on there) but that might cause more trouble than its worth, as I believe the ECS chipset in the 600 relies on this for its timings as well - this could a) skew the video modes by a factor, b) overheat and therefore risk damage to the chipset.

so BEWARE !!

let us know how you get on !

[Madgun68]

Here's a quick, cheap way to accelerate an A600:

Build (on the cheap) a device similar to a catapult. Place A600 on device. Launch A600. Gaze in astonishment at the speed in which your A600 now flies.

Just think of the amazing speeds your A600 can accelerate to with this simple and cost effective approach. :-D:-D

[xeron]

I wonder if you can overclock the ECS chipset in the A600, if you used a higher-speed rated 68000, and put heatsinks and fans on everything?

I mean, the ECS chipset in the A600 is basically the same as the one in the A500+, and only slightly modified from the OCS one in the original A1000, but with newer manufacturing processes. If you put a new 68000 in, and exactly doubled the clock frequency (14Mhz instead of 7), it might just work. Although your PAL output would be 30Khz instead of 15Khz, so you'd need a very forgiving VGA monitor.

(Note: If you try this, it almost certainly won't work, and will probably just break your A600. You do this at your own risk...)

[Samuar]

lol @Madgun68

nice idea m8.

However, does anyone have documents detailing the layout and specifications of upgrade boards? no one produces them anymore, which is why they are so expensive - but if several members of the community could gain access to the right information, perhaps we could start producing and shipping new accelerator/upgrade boards. if they are fast enough, and cheap enough, i suspect most of the community would be interested in buying them.

[Piru]

If you put a new 68000 in, and exactly doubled the clock frequency (14Mhz instead of 7), it might just work. Although your PAL output would be 30Khz instead of 15Khz, so you'd need a very forgiving VGA monitor.

Not a chance. It will never work this way.

You need to double the cpu clock while keeping rest of the clock signals untouched. See aminet hard/hack for instructions how to do this on A500 (it's quite easy since the 14MHz clock signal is available directly IIRC). In theory it might be possible to apply this hack to A600 aswell.

This is not overclocking the chipset itself though.

[xeron]

Piru wrote:
This is not overclocking the chipset itself though.

No, I know, but I was under the impression the A600 got the same clock for everything. I also didn't really think it would work, I was just go off into fantasy land really. Kind of in the same way Amiga 4000 owners fantasize about the "free beer" 8Mb chip jumper working ;-)

Even if you could boot an Amiga like that, the floppy drives wouldn't work any more with an overclocked paula... the doublespeed access to chipram would be a nice bonus.

[Matt_H]

Yes, it's a top-of-the-line 68000 at 20Mhz. Maybe I didn't look hard enough, but the only crystal on the 600 motherboard I saw was clocked at 28Mhz. Same with the 1200. I assume there's a dividing value somewhere else. The 600's default 68000 is actually an 8Mhz chip clocked down to 7. Time to check inside the machine again...

[bloodline]

Matt_H wrote:
Yes, it's a top-of-the-line 68000 at 20Mhz. Maybe I didn't look hard enough, but the only crystal on the 600 motherboard I saw was clocked at 28Mhz. Same with the 1200. I assume there's a dividing value somewhere else. The 600's default 68000 is actually an 8Mhz chip clocked down to 7. Time to check inside the machine again...

Yup the whole system comes off the 28Mhz crystal.

Thus the A500's 68K runs off a 4 times divider... and the A1200 runs off a 2 times divider.

As for over clocking the chipset... I don;t think so. The parts were never designed (or planned) to run faster than 28Mhz, and I think there were other timers on the system which would get out of sync if the system clock was changed.

Still it would be fun to try. The Monitor output would probably be totally unreadable though, I don't think the components used were high enough quality to run at those speeds.

IIRC Motorola actually ran the 68000 at 50Mhz in their own labs, but I don't think a comercial version was ever made. :-)

[Matt_H]

So we'd need a 1.4 divider for a 20Mhz chip. Or maybe overclock it to 28Mhz with a divider of 1. Where is this setting controlled from?

I did a quick glance through motorola's documentation. 68000-type chips in the 68pin Lead Quad Pack (that is the format used in the 600, yes?) look to be fully pin compatible (See this , page 173), even the 010.  Anyone got any 600 schematics?