New Commodore 64 and 1541 drop in replacement ROMs
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- čas přidán 27. 06. 2024
- A quick look at something else I've been working on for the C64 - modern ROM replacements!
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2:03 NONSENSE!! This sound effect is the best in the world!! You should put it on all your videos!!
Yes, it bugs me when replacement chips don't have the same form factor. Beautiful work.
So, you developed a ROM „down under“….. 😂
Great idea and products.
I need SX64 and C128 ROMS of this type! Take my moneh!! 🤑
Right on! I love the clean designs. Nice!
oooh, I'd love that PET character rom in a C128 version, and a 1571 (& jiffydos) rom, and Plus/4C16 roms, and... and... and... I think you've opened up a rabbit hole there chap, lol. What about "unnamed" boards so people can roll their own variants for the less popular roms (PET disk drives for example)
Superb work .
Nice work, Mark!
What a great idea. Well done Mark!
Wow, I never even thought of that as a possibility... I have a C64 as part of my collection, but I didn't grow up with it and haven't really got into it much, but there's a lot of other vintage hardware that uses those 24 pin DIP EPROMS that your approach will work for. I think I need to try this out myself.
Always love to see people bringing modern solutions to the C64. Great solution Mark👍
Wow! Great job! They really look nice in the 64 and the 1541.
Fantastic! Thank you!
Switchable Char ROMS! LOVE IT! The PET font is so much more attractive!
A couple years ago I found five breadbins (and five 1541s and a bunch more stuff) on the curb and many of them had a 4-Kernal switcher and one had a switchable CHR ROM, also with C64 / PET charset
Score!
Excellent work. They look so amazing! Will definitely add them to my wish list:) thanks A+
Great work!
Wow! What an awesome product! Now the not so easy to find or replace roms are inexpensive and so easy to replace! Brilliant! Thanks!
Super great ideas and solutions for C64 like to order later on. Regards
Nice work :)
I can't help myself. Every time I see EEPROM written, my brain automatically substitutes in REEEEEEEEEEEprom.
Those replacement roms are very elegant. Better than my double stacked adapter deal. As a fellow Aussie I immediately went and bought 2 (Kernal and Dual Char). I would Also like a basic rom but none in stock unfortunately.
Nice. I sent you an email in regards to the basic rom, let me know if you got it
Excellent stuff Mark. Will mostly definitely be checking some of these out for my modded C64/1541 setup. I’ve just received a rather damaged C128D that I’m planning on restoring. Is there any chance a similar set of replacement ROMS with JiffyDOS would be available in the future for the 128/1571 combo ?
No current plans for the 128 as they already use a 28pin ROM, so it's easy to use a standard 27CXXX EPROM.
@@TheRetroChannel Thanks for clarifying, I did have a doubt it would be required there. Need to get more familiar (through repairing) my new toy.
@75slaine No worries, good luck with the 128
Mark does it again !
Great idea using the smaller profile SMD so you can put the text on the top of the chip. These look great and the lower power consumption is a nice benefit.
5:06 you can use a three pin switch connected to a cable that leads to the switch outside, you don't need holes tho, there are spaces free between some expansion ports.
I haven't tried to build a slim PLA yet, but I do prefer being able to pull out and reprogram ICs if necessary. Still, having a drop in solution is a great solution for most people and these newer EEPROM ICs are much more robust than the old C64 ICs and could prolong the life of the original ICs because these old ROMs burn out from use (probably because they inefficiently sink a lot of current).
Was just wondering about the voltage and I/O specs of those replacements. I know not all ICs are created equal, and although the C64 is quite forgiving overall, it has some timing issues with anything outside its design specs (select min input voltage, rise time, slew rate, settling time, ground bounce, and sink current). EasyFlash and VSP issues can arise if the spec isn't quite right for some of its ICs.
That being said, ROM replacements are usually quite safe regardless as long as the output I/O voltages are 5V (3.4V min) and they aren't too slow and I don't doubt you've tried these yourself with some burn-in testing. Super Zaxxon, EasyFlash, VSP bug tests, etc.
Yep, no issues with the EF3, super zaxxon or triggering VSP bugs. The datasheet for the ATMEL 28C64 is available online, I'm using the 150ns version
Hello, I’ve got a couple of 1571 in need of some TLC. Reading occasionally never writing or formatting. Would you be able to make a video repairing/running diagnostic ? Let me know. Very nice video BTW. Nice new Rom chips too!!!!
czcams.com/video/hi_3T00MctI/video.html
Great stuff, Mark! Question; are these eeproms? As in; i would want to use a custom rom I made, would that be possible?
They are eeproms but need to be programmed before being soldered to the board so not suitable for custom ROMs
What a great work Mark 👍👍
It could be used theoretically also for the characters rom in the C128? Thanks 🙏
I haven't looked into the character ROM in the 128. From memory it has a set for the C64 and a set for 128. Not sure if it's a 24pin or 28pin in there
It's a 24 pin ROM using A12 to switch between the two fonts. So the same as your switched version but with the switch line being routed to A12 in the socket (pin 21) @@TheRetroChannel
I'm talking about the U18, the one that have the "national" characters. It's a actually a 2364, with that "odd" adapter directly from Commodore. I had to "build" one with a 2764, but the clearence is so low that I had to solder directly to motherboard w/o sockets. Your adapter would be GREAT! @@TheRetroChannel
Hmm, ok. I'll have a look at it tomorrow if I get a chance
Excellent work and products!!! Will you be selling blank ROM replacements?? Would love to use your products in my Commodore PET, VIC20, and Apple II computers
As you already know, it might happen
These are sweet! Will you do vic20, pet, 128 etc aswell?
VIC20 yes, 128 maybe, PET dunno. I'd like to get my hands on a PET first
@@TheRetroChannel Awesome, good replacements are sorely needed for all of the machines and drives.
Nice 👍 but isn't Jiffydos still a commercial product that requires a license?
In future, try watching the full vid before commenting. He said near the end that he purchased a license for JiffyDOS.
@@g4z-kb7ct one license isn't going to work, you need a license for each copy.
Each one has it's own license. I buy them before building the replacement - no license, no build
Is there a way we can program them if we buy them, like an adapter of some sort? This would probably be pretty useful for IBM 5150 ROMs too, especially the diag ROMs, but one of those is under active development and gets regular updates and improvements from the author.
Not with the current ones, but maybe I'll cook up something
One more thing! Would be nice if someone made or found a heat sink with a little pad on top to print the chip info underneath! Date codes and other info can get lost under there which might be useful or interesting to know.
I usually try to write that info on the underside of the chip before putting a heatsink on. Obviously it needs to already be socketed and there's only so much info you can squeeze onto the underside
"And overdoing with the sound effect" - .... that's what she said?
Are the EPROMs reprogramable in that package? They would be great for use in a VIC 20 too, plus I like to use custom boot screen colors on my C64.
Not for these, I might look into making something that can be reprogrammed but no promises :)
It would be great if you do. There are plenty of other machines that can use 2364s like the Atari 8 bit line and the IBM 6150, and a programmable one would be very useful for those. This design is so much neater than anything else out there.
Atari is a tricky one as they tended to use an inverted chip select. Not sure about IBM, or many others for that matter 😅
Jiffydos is about 60% compatible with original disk games, I have a few thousand and it failed with many of them. It also doesn't work with Action Replay, I haven't tested other utility carts.
Is that using JiffyDOS on the 64 side? What about JiffyDOS on just the 1541 with the original kernal on the 64?
@@TheRetroChannel It's hit or miss, lots of loaders at least in USA expect rom routines in certain places and call inside them, and the code is different or the offsets have changed and they fail. Early rapidlok and v-max doesn't like it. It was mostly with both enabled where problems arose though. It was enough to be annoying. I used JDOS way way more on my 128 as I used it for calling out and other stuff.
I've always wanted to design something like this using modern(ish) SMD EEPROM devices. I wanted to make them user programmable too, so that anyone with a programmer could burn whatever image they wanted on them. Unfortunately, my tiny brain couldn't come up with an elegant way to make them both readable on the computer and writable on the programmer. Are your designs user writeable?
They are not user writable unless you desolder the eeprom. Maybe I'll try and work out a solution in the future but for these I wanted to keep it as neat as possible (and somewhat match the look of the originals)
@@TheRetroChannel That's what I thought too. You need to program the EEPROMs using a SOIC adapter before soldering them on. I was actually thinking of designing a "programming adapter" PCB to translate the pinout back into 28C64 (128, 256 etc) provide an easy programming option for the user. Other stuff got in the way and I shelved this project.
@@TheRetroChannel They can be re-programmed without removing the chip. You just need to make an adapter that re-wires it to suit the SMD chip then program it as a 28C64.
Any chances we can get a version of the Basic/Kernal ROM used in the shortboards?
It might happen, but I'm prioritising 24pin roms as the 28pin stuff can be easily replaced by a 27CXXX eprom
@@TheRetroChannel That's understandable. Was looking at my VIC-20 the other day, and was thinking if replacement ROMs for the VIC-20 would be on the table?
Stay tuned 😉
Admittedly I have used the MiSTer FPGA C64 Core with JiffyDOS and a game I had as a kid "Rail Boss" does not work with JiffyDOS at least on MiSTer. Would love to see if it works on Real Hardware.
Nice. I'll look up the game and give it a test.
Just tried it out with a D64 image from wowroms copied to a real floppy. Worked fine with and without JiffyDOS, interesting game though. Maybe it's a PAL/NTSC thing, I used a PAL machine to test
Apologies I realised I was wrong. Its DolphinDos that has issues with Rail Boss and not JiffyDos.@@TheRetroChannel
Hi Mark, you have a typo in the title. :-)
Thanks! It's not the first time I've done that same mistake
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Funny old software now has licenses... lots of my old software does not, absolutely non and you bought it but were not allowed to copy it or distribute copies... sometimes only that, sometimes not even that.
Where do we get them?
Links are in the video description
Apparently Batman The Movie is not compatible with Jiffydos
Ok, I'll add that to the list of things to try
I tried it today and it worked with JiffyDOS and a real floppy. But as I don't have the original disks I can only test it with a cracked version found online
Eeeeee... T phone home....
Heh! Welcome to the 21st century. I made my own little 2364 to 28C64 adapter in the same DIP size as the original about 6 years ago ;-)
The "ultra reliable" GAL pla is far, FAR from just that I made several videos on it, the very fact it uses more than one chip makes its chance of failure greater than 1 chip...... there are some boards on pcbway for rom switching, one has 4 terminals at the end and I simply fitted a 3 way dip switch for 8 kernals....... If your board uses a controller to switch (arduino) etc then these have historically had some problems with some cartridges, like easyflash etc, 24pin roms are a pain in the arse to source nowadays .......
The thing with the GAL PLA is it's open-source. If it fails just make another one. I made my own CPLD-based PLA using a Xilinx XC9536 which is the same size as the original chip. If it fails I just make another one.
@g4z-kb7ct absolutely correct, but the nature of the gals does indeed cause them to fail, most chips available are pulls, I got into the whole PLA thing a while ago and made several videos, if you want the closest match to the original then it's definately the plankton ev, The combinatorial logic of the pla is well documented now, my 2p is that there enough to go wrong with old hardware without potentially adding more into the mix, I have spoken to the dev of the gal pla at length, and do applaud him for a low cost community board and his time developing it, But, as good as it is, ..... ultra reliable....... its not.
@g4z-kb7ct with the xilinx chip I reckon you probably as good as your gonna get , replacement pla wise, intake it that its the 5v tolerant version, one chip and sorted nice......
"Reliable" may have been a poor choice of words, "compatible" is probably what I was searching for. That being said I'm yet to have one go bad, apart from one that I killed by sticking it in a SID socket - damn 250407 boards! Not a big loss as they're cheap anyway. Still, I'd take a chip with 2 GALs over the original MOS PLA. Was yours bad from the start or did it develop an issue over time?
The Kernal switcher uses a pic to switch, I've been using it for a while and haven't had any issues with the EF3 or anything else so far. And I switch Kernals a lot so it's handy to be able to do it without opening the 64.
@TheRetroChannel the gal plas I had go bad went bad over time, made a few videos on it as unfortunately only 1 gal went bad and took a LOT of investigating, smoking a pla in a sid socket, priceless..... lol ..... ranks up there with me plugging one in upside down and blowing its entire arsehole out lol, It's the arduino rom switchers that tied into the keyboard line which affected the cartridge port
Ooh. Could these be tweaked for PET ROMS?
Possibly. But I'd want to get a PET myself before saying yes for sure.
@@TheRetroChannelJust make a programming adapter and sell that too then anyone with an eprom programmer can put anything inside the rom. Anyway, legally you can't sell any ROM you don't own so you can't sell replacement Commodore ROMs, period. Just sell blank chips and let the user do the programming. PET ROMs are 2532 or 2716 so easy to program with standard eproms. I know because in the past I fixed a couple of PETs and replaced the old MOS roms with eproms.
The lack of upgradability is a major drawback of modern machines 💾