Well... the "L88M"s I got from utsource were reprinted. The mask they printed on there was made up and a 2012 datecode also doesn't make too much sense:
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Carrera040 cloning
- Thread starter Bolle
- Start date
Well... the "L88M"s I got from utsource were reprinted. The mask they printed on there was made up and a 2012 datecode also doesn't make too much sense:
Its sad that these companies have to fake stuff like that. I can’t really see much reward for them doing it either. 90% of people using vintage stuff will know it’s fake. Unless this fake was made 20-25 years ago.
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The ones I got do have a FPU, so they are some kind of full 040.
They also don’t seem to run as hot as most of the other chips I have around but they’re far from being what I would consider cold running.
They are rock solid at 40MHz though and at least one of them also seems to take 50MHz just fine as well.
Still trying to see if they’re going to refund me because there’s obviously some faking going on here even if the prices weren’t actually too bad even for what I got considering they run fine at 40MHz.
They also don’t seem to run as hot as most of the other chips I have around but they’re far from being what I would consider cold running.
They are rock solid at 40MHz though and at least one of them also seems to take 50MHz just fine as well.
Still trying to see if they’re going to refund me because there’s obviously some faking going on here even if the prices weren’t actually too bad even for what I got considering they run fine at 40MHz.
Mine is also a full 040. No idea how they source these chips and where in the supply chain the faking is happening. I sent them a screenshot of the original listing and said that the item I received was incorrect and runs too hot for my purposes. I received a full refund and they did not ask me to return it. I never called it out as a fake, I just said it was the wrong mask, which they didn't argue with.
UTSource will refund you for that - definitely. They actually want to have a decent reputation. Raise a dispute already?Well... the "L88M"s I got from utsource were reprinted. The mask they printed on there was made up and a 2012 datecode also doesn't make too much sense:
I did, they're working on it.
That said, everything else I got with that order was perfect.
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I was also going to say, i got a batch of MC88916DW80's if you need them.
Ditto would love to get my hands on this thing. Saw it first on Action Retro. Bolle any info?
Shenanigans afoot! As always, massive thanks to @Bolle for posting the schematics and relevant info needed to clone this. Wouldn't have happened without that.
Interesting tidbits i've come up with: I can roughly confirm the acceptable clock range as per what @GeekDot posted in the hacking thread. The clock is incredibly fiddly to the point where I have some cases where the same type of GAL won't work. 15-47 of theoretical delay (by various loops through GALs of various speeds) seems to roughly be the range. Around 30ns of delay also seems to be problematic. If someone else designs their own clone, be prepared to trial and error it.
Additionally, the less delay (while still being in operable range) improves the 68040's ability to access the 68030 bus: As the delay increases, bus performance (memory read/write) decreases. On the longer delay side @ 45mhz - ~113% SE/30 memory performance as measured by Snooper 2.0. On the fast side, 131% (@45). Norton system info gives more detail on this. I have not decided which I plan to keep and try to validate stability.
By comparison, 68030 accelerators Diimo and Powercache are approximately 2x faster at accessing main memory.
As the 68040 has sync bus cycles only I assume the logic to adapt the 68030 async cycles (used by main memory) has to insert wait cycles til the timing lines up just right, and by playing with the delay, it must shave a few cycle or two off sometimes as the clocks are not phase locked nor even multiples. With phase locked to the system clock (and frequency doubled), no CPUclk delay is required for maximum performance. At 31.33 mhz snooper saw 111% SE/30 performance. This decrease to 100% if there is a delay. Better performance than expected, for such a large decrease in clock speed.
My clone's cache section seems to be happy at 45mhz without any fuss. I did use faster rated SRAM and a few other minor tweaks, but this was a surprise to me.
Do not order 68040 from UTsource. They sent me a remarked original 0.8um 68040 that has very little hope of hitting 40mhz (not without cooking). Currently battling to get a refund, preferably without shipping the stupid thing overseas.
Atmel 17C65 works just fine for the FPGA PROM. Atmel was so kind as to post an AVR example of how to write a programmer, which I updated to work on any AVR-based Arduino (I'm lazy, sue me). I'll toss it on Github if anyone has interest.
Nice cheap heatsink that is a perfect size for a 68040. Bring your own thermal tape.
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Nice work!
UTsource is definitely not a solid supplier, you can get lucky and find old ICs that aren't available elsewhere, but you can also be supplied with remarked lower spec chips or complete fakes. And their support is definitely not the most helpful or willing. Always a Fun™ gamble.
UTsource is definitely not a solid supplier, you can get lucky and find old ICs that aren't available elsewhere, but you can also be supplied with remarked lower spec chips or complete fakes. And their support is definitely not the most helpful or willing. Always a Fun™ gamble.
Yeah. Figured in for a penny, in for a pound. Thankfully, the things I did actually need to be legit were: Both FPGAs, clock generator, Config prom, GAL20V8s. I ordered a couple of TAG RAMs from them also, but I didn't use them as they were a little rough. Hadn't seen TAG SRAMs with the newer IDT logo either.
Wait a minute, did you design a socketed version of the Carrera 040??
Oh wow, what a great idea! Are these one-offs or are you planning on making more?
Thanks for the part number for the 040 heatsink, I needed to get one. Do you have a recommendation on what thermal tape to use?
I tried some thermal tape, but either the heatsink or the 68040 wasn't quite flat so the contact was poor. Also, it is very hard to get quality thermal tape. So I went with paste. I've attached a STL for some clips I designed that are perfect for that heatsink or any other heatsink around 2.5-3mm thick at the base. You'll need a 3D printer that can do ABS, Nylon, or another high temp tolerant plastic. PETG, I wouldn't recommend using if there isn't a fan on the heatsink as PETG gets soft north of 60 deg C or so.
No plans to mass produce... sourcing the obsolete parts required is a massive pain, and assembling them is time consuming. I had to order the FPGAs, Clock generator, TAG SRAM, and GALs from UTsource, which was an annoying process both before and after. I'm still wrestling them on the 68040 I tossed in on a whim.
I did make a second Diimo as for some reason
I ended up with a mess of spare parts. I'll probably also make a second SockeCarrera at some point to use up spares. These may get traded away at some point.
Nice, that's an elegant design with the combined flexure and latching.
Let me know if you are interested in letting go of the potential future second SocketCarrera in the future.I did make a second Diimo as for some reason
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