Amiga 1200 FPU Part 2 - Adding a 40Mhz Crystal Oscillator

[@rebeccaschade3987]

I have an FPU on my accelerator card as well, despite it being functionally useless on an A1200. It's a case of "yes, but I CAN have it there." It needs to be maxed out, it's that simple. Cool little project :)

[@stog33]

Nice video Glen, Amiga PCB explorer, what a fantastic resource to have, used it several times myself for troubleshooting some A500s

[@CRG]

It is a great tool. Really helped me with that A500+ board I fixed a while back.

[@YogSothoth1969]

Very cool you got it working correctly! Best wishes and o7 Cmdr, Michael (aka Cmdr Rory MacNab)

[@CRG]

Thanks, happy to have it working at full speed. I see there's been a few updates for Elite recently, I really should check them out.

[@YogSothoth1969]

@@CRG Oh yes, if you haven't been in for quite some time there are really updates, the Thargoids are very active at the moment :-)

[@miked4377]

good to see you back....after the long time you were gone...i am surprised it didnt run proper the first time...but..it does now..

[@CRG]

Thanks, it's great to be back. The absence was down to holidays, work and my first dose of COVID which absolutely wrecked me.

[@giuseppelavecchia775]

A1200 stupendo,pompato molto bene!.ottimo lavoro

[@imqqmi]

Did you cut the CLK trace to the 68882 or use a piece of tape to insulate the 14MHz signal? I think I'll add this to my ReAmiga project, thanks!

[@CRG]

As you'll see in the video I just lifted the pin on the fpu. That's enough to get it to clear the socket. But I suppose if you wanted to go to 40mhz from the start you could fit a plcc socket but remove that pin from it or if you were mounting the fpu direct just lift that one pin from it.

[@CRG]

My apologies, I was getting mixed up. I show the lifting of the pin in the original fpu mod video, not this one!

[@imqqmi]

@@CRG Thanks! I think I'm going to solder it directly to the board and put a thin strip of kapton tape under pin 11. That way I can keep everything stock. And use a 14 pin socket so that I can swap out oscillators and try to overclock it a bit, see how far it can be pushed.

[@CRG]

Sounds like a good idea. I'd be interested to know if you can get any more than 40mhz out of it.

[@imqqmi]

@@CRG Unfortunately no, I did an overclock of 44.9MHz but it wasn't stable, hangs, errors etc. And at 65MHz I got a yellow boot screen ;) So 40MHz is as high as you can go and have a stable system. I haven't tried different 40MHz FPUs but I suspect they're all the same. I don't have any other oscillators above 40MHz to try but less than 10% boost isn't really worth it.

[@Raketenclub]

wow, very cool. have to do that too. just because i can :D ... i already thought of solder an fpu socket and have already bought fpu and stuff... now need a new crystal. thank you so much :D awesome mod. even possible without a tf.

[@remijakobsen1848]

Great video! Many progs require FPU or can use a FPU: Raytracing 3D like Real 3D, FPU versions of spreadsheet progs, fpu ver of compression/decompress software, Amiga UNIX, emulators,

[@ps3customgamer]

Did you consider a clock generator so you could make later adjustments

[@CRG]

I am now lol

[@MrLukealbanese]

Great to see you back Glenn 👍👍👍

[@CRG]

Over the last 2 months I've been away on holiday, had my first brush with COVID (wrecked me for a couple of weeks) and just been very busy with work. It's great to be back though, really missed my retro projects.

[@ProtekNickz]

Great work doing this CRG, Just a quick question about this mod, Wont this shorten the life of the FPU or Amiga or will this run fine with no sever problems?, Asking as I may do this to my own amiga, And yes I know you give no guarantees for doing this my self ect.. ect.. xD, Keep up the great work!.

[@CRG]

No it won't effect the Amiga in any way. Will it shorten the life of the FPU... I suppose it might if you overclock it. That will generate more heat in the chip although I'd think any such risk of doing so is negligible. Do bear in mind that if you fit an 060 accelerator this mod becomes redundant as that chip will disable any external FPUs.

[@ProtekNickz]

@@CRG cheers for the reply and info, Great Channel.

[@10MARC]

Art Department Professional, ImageFX, Vista Pro, Imagine, Turbo Silver, Lightwave... Just about 10% of the Amiga Software that uses an FPU. It all depends on what you use an Amiga for. Video Games? Don't bother with a FPU. Creativity and Graphics (like what it was designed for) - then an FPU is a requirement.

[@CRG]

But if you can have an FPU, even if it won't be used then surely that's excuse enough to fit it 😂 In my case and to be honest it'll probably not get much use but I'm just happy to have it in there and running at the correct speed.

[@MichiMilchmelker]

it would be intressting for me, when you use the fpu how the mpeg1 performance goes up ! i find a nice sweetspot for ffmpeg to creat a full movie to 300mb for the tf1230 on a1200 but i had to switch the mpeg lib from a fpu one to a non-fpu mpeg lib. i would really like to know if a fpu "addon" would make the mpeg playback better. i think amiga amp want a fpu too

[@craigbudd9866]

Would this work with the tf1260 running a 68060 without a fpu

[@CRG]

No it won't work. The 060 does not work with an external fpu but even if it could this fpu would be a severe bottleneck. If you're running an 060 LC or EC it's best to think of it more like a crazy fast 030 and run software compiled for that chip.

[@DIYTinkerer]

Great video, 👌 aren't there any libraries that can be replaced to utilise the FPU?

[@Google_Is_Evil]

Trying to get a clock signal from that far away from the FPU and not using wiring that is meant to transport these frequencies will very likely have mangled the signal to a point that the FPU would only switch on every second waveform (more or less) explaining why it went to 22.something MHz. I would try higher frequencies with the dedicated xtal setup you have now. I think there is a good chance that you will hit the 54MHz or even higher. Worth a revisit?

[@Tjuwantjutju]

Happy hello everyone

[@DAVIDGREGORYKERR]

If the Custom MOS chips could be recreated using FPGAs and CPLDs then it might be possible to rebuild it so that it would work at the sort of speeds that modern day computers operate at but a Graphics Card would be required as it would most likely be hard to get the video side to work at the frequencies involved.

[@CobraTheSpacePirate]

It looks like it was running exactly half the speed. Like it only got every other clock edge.

[@Drew-Dastardly]

I remember back in the '90s when I souped up my A1200 with an '030 @ 50MHz and fast RAM I always wanted to fill that spare socket with an FPU. I wisely spent any spare money on a SupraFAX 14.4 modem (free firmware upgrades to 28.8k, 31.2k). Then a proper multisync monitor with VGA and 15kHz PAL modes. For Lattice/SAS C++ dev work the CPU accelerator, my 3.5" HDD to 2.5" IDE hack and the monitor where essentials. The modem and RoxBox (anyone remember that?) also essential on the high seas. I always had an itch for that FPU but I don't know why.

[@theamigashow9506]

That's some surgery! It worked too :D

[@espenmostue5136]

Back in the days, production was not as accurate as today, therefore they had to test every chip. And chips that did not meet top quality was sorted out into lower classes and stamped with a lower clock speed (where they were running reliably) and sold as a cheaper variant to cut cost of production. Intel did the same with their CPUs (x86-series). That's why some CPUs and FPUs can be over-clocked and some can not..

[@EduArana]

Super hack! love it!

[@CRG]

Thanks, glad you enjoyed it.

[@Rodde718]

Also. Probably some emulators for consoles or 8 bit computers could be a little boost. But overall. Your Amiga is more compatible now. Sometimes softwares screaming for fpu. Which means you need to replace libs with non fpu. Which leads to you dont have to think soo much. Congratulations, in my opinion you have the best Amiga setup. Considering both boost and compabiliy. whdload made any amiga a far better compabiliy we could ever think. You will be able to run most of the softwares and demos now. Some of them to slow but will boot. Now replace that ec030 with a full mc68030 😉🤣

[@CRG]

Emulator on the Amiga is something I've wanted to look at for a while. I'll try them and see how it goes.

[@Rodde718]

Search for the devs and libs compiled with fpu. Thats what i think could help by trying to unload the 030 as much as possible. Im not sure. But with alot of tweaks you might be able to play mp3 with the right drivers with amigaamp or similar. Actually with the 14bit ahi driver most likely some mono settings in low quality. Its possible to listen to mp3. Dont even try the regular 8bit sound. Its terrible. Question is if 68882 40mhz fpu is enough. I did this with my blizzard 1230 mk iv 50mhz cpu+fpu as a kid. I could play. With the right drivers which ones i cant remember. But i was able to use things like Deluxepaint at the same time. Look for fpu compiled mp3 codecs and maybe fpu compiled ahi drivers. And any libs that the amp software uses.

[@LaserFur]

You should get some wire wrap wire. it's smaller than the wires you are using.

[@WX4CB]

not to mention some heatshrink :D

[@CRG]

I just like to use what I have. I didn't think about heat shrink until after, I might go back and redo it but ultimately it'll be fine as is.

[@Raketenclub]

btw, i accidently bought a cheap make fo tf1230 at ebay, beware of the black pcb made tf! they are poor and equipped with a 33mhz cpu, which will stall after 10 minutes without active cooling. this made me headakes until i recognised i was fooled by an ebay seller. got my new tf from amigastore directly for cheaper.. and with a nice 50mhz goldcap cpu and made with much love!

I watched the previous part to because I bought the same FPU's I think, ebay from china, think they where like 2€ a pop and was also worried they might be fake. Mine has the same Print and numbers except the last line is different. 3rd line on mine is QEED0823 But both of my chips have the exact same print tough, so if they are fake they are changing it between batches I guess. But idk can original chips have the exact same print? I also bought some ceramic 33Mhz 030 QFP cpus for my 68K system, might be fakes to becsue the print is identical on both. Anyways cool to see that the FPU seems stable at 40Mhz, my board will only allow for 33Mhz max anyways. Grate videos as always with good information!

[@CRG]

My chips came from AliExpress but working happy at 40mhz so I can only assume it's real. I'm not sure but I'd expect any chips of the same spec to have the same part number, I expect the 3rd line might relate to a batch number. I hope your chips work, good luck.

@@CRG There is forum post on 68KMLA now from 2024 with images of fake once. Mine is there twice 😅 Both yours and mine has 1C12R and they where according to there list made from 1990 to 1993 and both yours and mine has date codes from the year 2000, 2008 for me and 2012 for yours. The forum thread is called "Sourcing Legit MC68882 FPUs - Data" and google should find it. Anyways just figured your might find it interesting and yea I cant post the link to the forum post but assuming youtube dont block my message your should find it if you have not already read the thread. Btw time just flys, feels like I wrote the last post a few months ago 😆

[@mariotazo2860]

MC68882 slow FPU, very, very slow...

[@benjaminwirth5192]

Back finally👍