6 ms·

No, it is not Commodore 64 anymore. It won't feel like one, you can as well run an emulator. I get it, FPGA is more faithful reproduction, than pure software, b

No, it is not Commodore 64 anymore. It won't feel like one, you can as well run an emulator. I get it, FPGA is more faithful reproduction, than pure software, but it is not a real thing, and will never be.

bullen 3y ago
100% agree
nemo8551 3y ago
Well that’s just like your opinion man. But I get it, it’s really hard to accurately replace legacy components as time moves on, it probably will feel like one but as it’s not all original it will never meet an unattainable expectation.
vidarh 3y ago
For e.g. the SID, where a bad implementation might work but affect the sound, you might have a point, but for the CIA's this a meaningless purity test and sophistry. Put another way: You can pull an 8520 from an Amiga and put it in a C64 and most users will never know the difference (been there, done that, horrified my parents who saw me involved in surgery on our two computers) because most C64 software never uses the clock function of the 6526. As long as it provides the IO functions you mostly rely on, most users will never know nor care about the difference.
- SomeoneFromCA 3y ago
  No, it is not "sophistry". There is a reason why Apple-I commands these high prices- because it is a piece of history, a slice of technology of the era. If I buy Commodore 64, I won't be buying it for replaying old games, it is completely pointless excercise, I can just buy RPi for that, I will be buying it to have a historical artifact. Now what kind of historical artifact would it be, if the only thing left is the PCB, and everything else are Xilinx IC's designed in 2020s, 40 years later?
  - vidarh 3y ago
    If you're buying it as a historical artefact and not to use it, then surely it doesn't matter if it's non-functional either? In that case this isn't for you, and that's fine, but arguing it's not a Commodore 64 any more is sophistry. It's not an "100% original unchanged" Commodore 64, sure. Very few people care about that.
    - SomeoneFromCA 3y ago
      Working historical artifact are way more valuable then non-working. I am surprised so many people do not understand that.
      - wkjagt 3y ago
        I agree. And it's not just about monetary value. There's just something beautiful about a 40 year old computer still working perfectly. The fact that it's all original is almost a necessity for me to enjoy it to its fullest. I love programming these old machines in assembly language, while at the same time doing my best to understand what is going on inside the machine with each instruction. Replacing original parts with microcontrollers would take away a lot of that pleasure.
        SomeoneFromCA 3y ago
        precisely my point. I would certainly buy an Apple-1 if it were not as pricey as it is now.
        vidarh 3y ago
        If you want to use them, why does it matter if a chip has been replaced? To me, that is what is bizarre. I get the appeal of preserving some. I get the appeal of using some. I don't get the appeal of insisting on purity and retaining only original parts for something you want to actually use, especially when that increasingly means being unable to use these machines because parts are becoming harder to find. > Replacing original parts with microcontrollers would take away a lot of that pleasure. Why, when these parts react to the same electrical signals in the same way? In this case it's also not a microcontroller but an FPGA. The contents of the package is different, but the contents of the package also changed during Commodore's own production runs e.g. the change from 6526's to 8521's.
rcarmo 3y ago
Last time I wanted to fiddle with a C64, I just went and flashed bmc64 (https://github.com/randyrossi/bmc64 https://github.com/randyrossi/bmc64) to an SD card. Even an original Raspberry Pi 1 does a decent job of emulating it.
- SomeoneFromCA 3y ago
  Exactly mt point, no point in buying a bunch of Xilinx FPGA's and calling it Commodore 64.
wkjagt 3y ago
I think the point of the J-CIA is to replace a failing CIA in an actual C64. However, that's not what the title of this HN post is about, so I'm not sure what is going on. Regardless, I think making a replacement CIA is very cool, noble even, and I would be happy to buy one if a CIA in my Commodore failed, if it meant having a useable C64 instead of an unrepairable one. But I do agree with you, that building a completely new C64 out of FPGA replacement parts would feel very weird to me. I wouldn't feel like it's the real thing, even if it behaves exactly like one. The big advantage though, if it's a 100% faithful reproduction, would be that it physically behaves like the real deal, meaning you can plug in actual cartridges, build things that connect to the user port, etc, which are things you can't do on an emulator. For now though, I'm just happy mine still works (even though I kinda want to get a C64C instead of my bread bin).
- SomeoneFromCA 3y ago
  Oh, yes I agree. It is a necessary compromise, much like removing Rifa and electrolyte caps. I would still preserve the original broken IC in the C64's empty internal space, secured somehow, to keep the history intact.
TonyTrapp 3y ago
I wouldn't equal the possibility of taking a C64 with one or two broken chips and replacing them with a cheaper, more reliable modern equivalent to tossing the whole machine away and going 100% emulation.
- SomeoneFromCA 3y ago
  Neither would I, but this is not what the title says.
varispeed 3y ago
It is the real thing. It does the same thing, just using different technology. It's a fully digital chip, so it doesn't matter if logic is fixed on the die or "fused" on FPGA. It does the same function. The logic could as well be implemented in software - the reason it isn't and it wasn't in the original C64 is because it was not possible then. Programming this logic on a CPU would have required a very fast microcontroller, that would probably be more expensive than the whole computer. Even today, not many MCUs would be capable of emulating the CIA and keep up with all the timings. Mind you there is a difference in creating a software emulator that runs within the host computer versus emulating a chip that responds in real time to the electric signals.
- SomeoneFromCA 3y ago
  I do not need this condescending lecture about the merits of programmable logic over CPUs and emulation. The difference is not technical or even technological; the actual difference is social. Anything that it is not period-accurate is going to erode the historical value of the artifact, until the point when everything inside is a bunch of fpga's on sockets.
  - RetroTechie 3y ago
    The value of "historical artefacts" is determined by how many specimens remain, and how sought after they are. For whatever reason. Aftermarket / modern replacement parts cater to a different market. They don't 'dilute' the historic value of original parts. There is considerable overlap though. If anything, availability of modern replacements eases demand for original parts. Helping to keep those available for purists, musea, reverse engineering etc (and their prices reasonable). This should make both purists & non-purists happy.
    - SomeoneFromCA 3y ago
      No need in italic font and other passive aggressive stuff. Ask any old hardware enthusiast if they prefer an actual exact silicon level replica of SID or modern fancy shmancy FPGA replacement thing - I guarantee you majority would want the precise replica. Because why people content with these FPGA ugly looking quasi-substitutes, cause there is no actual period-accurate substitutes are available. In any case a "Commodore 64" made entirely from components invented in 2020s should be called C64 anymore. It is a replica, a decent one, but not the real thing.
crote 3y ago
That completely depends on your use case. Want to have it collecting dust in a museum? Sure, you're going to want the original. Nobody is interested in an FPGA for that. Want to actually use it? If an FPGA is close enough that it is literally impossible to tell the difference in a black box comparison, for all intents and purposes it is the original. Emulation simply isn't accurate enough for that, but FPGAs can be 100% cycle-accurate. And this means you don't need to risk wear or damage on your genuine C64 just to experience what it is like to use a C64.
- SomeoneFromCA 3y ago
  Emulation is very close to 100% cycle accurate for many, many machines. You would practically not deal with this problem anyway. Now, I may want to tinker with my computer on a board level, making a period-accurate hardware-tweaks for the machine, how exactly I'd accomplish that, if everything is just a big FPGA? Now, having IC'level FPGA substitute for big chips on the original board is a bit better than one big flat fat IC, but it still a different machine and cannot be called C64, as much as a Ford-T is not a Ford-T if you put a modern electric motor to it, even if you tweak it to sound and handle exactly like T does.
tyingq 3y ago
I don't know that for a parallel/serial/rtc chip you would really see any difference. I can see your point for some of the harder to emulate parts like the SID.
snvzz 3y ago
Once configured, a FPGA is the hardware that's configured into it. It's cheaper than an ASIC, unless you make a shitton of them. The newly-made design, be it in FPGA or ASIC form, is not the original MOS chip. But it could indeed behave identically. ASIC advantages such as lower power consumption and higher achievable clock speeds at a given node, are advantages relative to the FPGA. Not advantages relative to the original MOS chip, which dirt cheap FPGAs can vastly outdo, and only need to match for the purpose.
dusted 3y ago
FPGA is in absolutely no way more faithful, which FPGA implementation has 100% compatibility with all internal and external interfaces ?
tenebrisalietum 3y ago
The 6526 is infrastructure--it's a timer, clock, and I/O chip and doesn't really have anything to do with the interactive look and feel of the system. So an FPGA here doesn't harm the C64's soul one bit, if it works exactly like the original. Honestly it would have been cool if they added a battery and maybe an extra register to indicate its presence; having the TOD clocks keep their time between power cycles would be cool. Edit: If replacing a dead 6526 I would keep the dead one too. :)
rasz 3y ago
the Audiophile argument
nullsmack 3y ago
This is a silly argument. FPGAs are not emulation. They implement logic at just as low a level as an ASIC. One day even working original C64s will stop working. You can't get original parts anymore. This is as good as it gets for fixing those.

bullen 3y ago

100% agree

nemo8551 3y ago

Well that’s just like your opinion man. But I get it, it’s really hard to accurately replace legacy components as time moves on, it probably will feel like one but as it’s not all original it will never meet an unattainable expectation.

vidarh 3y ago

For e.g. the SID, where a bad implementation might work but affect the sound, you might have a point, but for the CIA's this a meaningless purity test and sophistry. Put another way: You can pull an 8520 from an Amiga and put it in a C64 and most users will never know the difference (been there, done that, horrified my parents who saw me involved in surgery on our two computers) because most C64 software never uses the clock function of the 6526. As long as it provides the IO functions you mostly rely on, most users will never know nor care about the difference.

SomeoneFromCA 3y ago
No, it is not "sophistry". There is a reason why Apple-I commands these high prices- because it is a piece of history, a slice of technology of the era. If I buy Commodore 64, I won't be buying it for replaying old games, it is completely pointless excercise, I can just buy RPi for that, I will be buying it to have a historical artifact. Now what kind of historical artifact would it be, if the only thing left is the PCB, and everything else are Xilinx IC's designed in 2020s, 40 years later?
- vidarh 3y ago
  If you're buying it as a historical artefact and not to use it, then surely it doesn't matter if it's non-functional either? In that case this isn't for you, and that's fine, but arguing it's not a Commodore 64 any more is sophistry. It's not an "100% original unchanged" Commodore 64, sure. Very few people care about that.
  - SomeoneFromCA 3y ago
    Working historical artifact are way more valuable then non-working. I am surprised so many people do not understand that.
    - wkjagt 3y ago
      I agree. And it's not just about monetary value. There's just something beautiful about a 40 year old computer still working perfectly. The fact that it's all original is almost a necessity for me to enjoy it to its fullest. I love programming these old machines in assembly language, while at the same time doing my best to understand what is going on inside the machine with each instruction. Replacing original parts with microcontrollers would take away a lot of that pleasure.
      - SomeoneFromCA 3y ago
        precisely my point. I would certainly buy an Apple-1 if it were not as pricey as it is now.
      - vidarh 3y ago
        If you want to use them, why does it matter if a chip has been replaced? To me, that is what is bizarre. I get the appeal of preserving some. I get the appeal of using some. I don't get the appeal of insisting on purity and retaining only original parts for something you want to actually use, especially when that increasingly means being unable to use these machines because parts are becoming harder to find. > Replacing original parts with microcontrollers would take away a lot of that pleasure. Why, when these parts react to the same electrical signals in the same way? In this case it's also not a microcontroller but an FPGA. The contents of the package is different, but the contents of the package also changed during Commodore's own production runs e.g. the change from 6526's to 8521's.

rcarmo 3y ago

Last time I wanted to fiddle with a C64, I just went and flashed bmc64 (https://github.com/randyrossi/bmc64 https://github.com/randyrossi/bmc64) to an SD card. Even an original Raspberry Pi 1 does a decent job of emulating it.

SomeoneFromCA 3y ago
Exactly mt point, no point in buying a bunch of Xilinx FPGA's and calling it Commodore 64.

wkjagt 3y ago

I think the point of the J-CIA is to replace a failing CIA in an actual C64. However, that's not what the title of this HN post is about, so I'm not sure what is going on. Regardless, I think making a replacement CIA is very cool, noble even, and I would be happy to buy one if a CIA in my Commodore failed, if it meant having a useable C64 instead of an unrepairable one. But I do agree with you, that building a completely new C64 out of FPGA replacement parts would feel very weird to me. I wouldn't feel like it's the real thing, even if it behaves exactly like one. The big advantage though, if it's a 100% faithful reproduction, would be that it physically behaves like the real deal, meaning you can plug in actual cartridges, build things that connect to the user port, etc, which are things you can't do on an emulator. For now though, I'm just happy mine still works (even though I kinda want to get a C64C instead of my bread bin).

SomeoneFromCA 3y ago
Oh, yes I agree. It is a necessary compromise, much like removing Rifa and electrolyte caps. I would still preserve the original broken IC in the C64's empty internal space, secured somehow, to keep the history intact.

TonyTrapp 3y ago

I wouldn't equal the possibility of taking a C64 with one or two broken chips and replacing them with a cheaper, more reliable modern equivalent to tossing the whole machine away and going 100% emulation.

SomeoneFromCA 3y ago
Neither would I, but this is not what the title says.

varispeed 3y ago

It is the real thing. It does the same thing, just using different technology. It's a fully digital chip, so it doesn't matter if logic is fixed on the die or "fused" on FPGA. It does the same function. The logic could as well be implemented in software - the reason it isn't and it wasn't in the original C64 is because it was not possible then. Programming this logic on a CPU would have required a very fast microcontroller, that would probably be more expensive than the whole computer. Even today, not many MCUs would be capable of emulating the CIA and keep up with all the timings. Mind you there is a difference in creating a software emulator that runs within the host computer versus emulating a chip that responds in real time to the electric signals.

SomeoneFromCA 3y ago
I do not need this condescending lecture about the merits of programmable logic over CPUs and emulation. The difference is not technical or even technological; the actual difference is social. Anything that it is not period-accurate is going to erode the historical value of the artifact, until the point when everything inside is a bunch of fpga's on sockets.
- RetroTechie 3y ago
  The value of "historical artefacts" is determined by how many specimens remain, and how sought after they are. For whatever reason. Aftermarket / modern replacement parts cater to a different market. They don't 'dilute' the historic value of original parts. There is considerable overlap though. If anything, availability of modern replacements eases demand for original parts. Helping to keep those available for purists, musea, reverse engineering etc (and their prices reasonable). This should make both purists & non-purists happy.
  - SomeoneFromCA 3y ago
    No need in italic font and other passive aggressive stuff. Ask any old hardware enthusiast if they prefer an actual exact silicon level replica of SID or modern fancy shmancy FPGA replacement thing - I guarantee you majority would want the precise replica. Because why people content with these FPGA ugly looking quasi-substitutes, cause there is no actual period-accurate substitutes are available. In any case a "Commodore 64" made entirely from components invented in 2020s should be called C64 anymore. It is a replica, a decent one, but not the real thing.

crote 3y ago

That completely depends on your use case. Want to have it collecting dust in a museum? Sure, you're going to want the original. Nobody is interested in an FPGA for that. Want to actually use it? If an FPGA is close enough that it is literally impossible to tell the difference in a black box comparison, for all intents and purposes it is the original. Emulation simply isn't accurate enough for that, but FPGAs can be 100% cycle-accurate. And this means you don't need to risk wear or damage on your genuine C64 just to experience what it is like to use a C64.

SomeoneFromCA 3y ago
Emulation is very close to 100% cycle accurate for many, many machines. You would practically not deal with this problem anyway. Now, I may want to tinker with my computer on a board level, making a period-accurate hardware-tweaks for the machine, how exactly I'd accomplish that, if everything is just a big FPGA? Now, having IC'level FPGA substitute for big chips on the original board is a bit better than one big flat fat IC, but it still a different machine and cannot be called C64, as much as a Ford-T is not a Ford-T if you put a modern electric motor to it, even if you tweak it to sound and handle exactly like T does.

tyingq 3y ago

I don't know that for a parallel/serial/rtc chip you would really see any difference. I can see your point for some of the harder to emulate parts like the SID.

snvzz 3y ago

Once configured, a FPGA is the hardware that's configured into it. It's cheaper than an ASIC, unless you make a shitton of them. The newly-made design, be it in FPGA or ASIC form, is not the original MOS chip. But it could indeed behave identically. ASIC advantages such as lower power consumption and higher achievable clock speeds at a given node, are advantages relative to the FPGA. Not advantages relative to the original MOS chip, which dirt cheap FPGAs can vastly outdo, and only need to match for the purpose.

dusted 3y ago

FPGA is in absolutely no way more faithful, which FPGA implementation has 100% compatibility with all internal and external interfaces ?

tenebrisalietum 3y ago

The 6526 is infrastructure--it's a timer, clock, and I/O chip and doesn't really have anything to do with the interactive look and feel of the system. So an FPGA here doesn't harm the C64's soul one bit, if it works exactly like the original. Honestly it would have been cool if they added a battery and maybe an extra register to indicate its presence; having the TOD clocks keep their time between power cycles would be cool. Edit: If replacing a dead 6526 I would keep the dead one too. :)

rasz 3y ago

the Audiophile argument

nullsmack 3y ago

This is a silly argument. FPGAs are not emulation. They implement logic at just as low a level as an ASIC. One day even working original C64s will stop working. You can't get original parts anymore. This is as good as it gets for fixing those.