User avatar
intric8
Seattle, WA, USA
Website

Posted Wed Oct 13, 2021 9:56 pm

Hey Folks,

If I remember correctly a few of you here are owners of the original C64 Reloaded (MK1). I was able to finally beat my friend in arm wrestling and get an MK1 for myself last week. ;)

The reason I wanted it over my MK2 was so I could use a Wifi modem with it without any hassles or screen garbage/noise.

However, I soon discovered I needed to make my own Kernal ROM. So, with the help of my friend Crispy, I ordered the proper EPROMs from DigiKey. Meanwhile, he taught me how to burn the ROMs using my Mac (all the tutorials and how-tos out there are for Windows folk, as usual). I plan on making a nice little mini-guide for others who would like to burn their own kernals using a Mac can follow in my footsteps.

I got everything working and burned the ROM.

Now, the way the chip works is kind of interesting. In an original C64 there are 3 separate ROM chips on the motherboard: BASIC, Character and Kernal.

With the MK1, you are to put all of those on 1 single ROM. In addition, there is space to support 2 character maps and 2 kernals. Excited and giddy, I made copy/pasted an original kernal ROM in one space, and created a customized JiffyDos kernal for the second space (with a black screen and white text, like some of the CMD disk software looks, which is nice).

Burned the ROM, verification passed.

Plopped it in the one remaining empty socket and flipped on the power.

Bam! Gorgeous and nostalgic light blue and dark blue BASIC C64 screen. Sweet!

Then I looked over at the instructions on how to flip to the alternate kernal.

iComp Wiki:
If you press and hold the RESTORE key for more than three seconds, the C64 Reloaded will switch to the other Kernal ROM upon release of the RESTORE key.
I press and hold the RESTORE key for what was probably more like 15 seconds.

Nothing happens. Not even a flicker.

So I do what we always go do at a time like this, I run to Google.

All I could find was a mention by MtnBuffalo having a similar problem. For him, holding the RESTORE key for 3+ seconds, releasing the key and then rocking the power switch to reset did the trick for him.

Now that does cause a brief flicker for me but nothing changes. It looks more like it's trying to change its character set or something, but simply returns the normal default blue CBM screen.

Anyone else with an MK1 get this to work? Does it make a difference I'm in NTSC land and this is a feature PAL machines use? (or should I be using a different key combination?)

I have 2 extra EPROMS in case my changing some of the color codes borked it (but that just seems so highly unlikely - but who knows?).

User avatar
Zippy Zapp
CA, USA

Posted Thu Oct 14, 2021 7:59 am

I have an MK1 and I haven't touched it in a year or more. I don't remember having any problems switching ROMs but I will test it and see since it was so long ago.

Did yours not come with the original ROM? If you need a copy I can burn you one and send it or I can dump the ROM and send you the BIN.

I get why they consolidated it to one EPROM but I prefer the way Jim Drew's ICS64S works especially with an OLED screen attached. Anyway, It is about time for me to pull the MK1 out for testing a few VIC chips anyway.

User avatar
intric8
Seattle, WA, USA
Website

Posted Thu Oct 14, 2021 8:10 am

Did yours not come with the original ROM?
No, I bought it off a friend and that wasn't part of the deal. I needed to populate all of the sockets except for the PLA iirc.

That meant I needed to learn how to burn EPROMs finally - and I did! The MK1 works beautifully with the default CBM blue BASIC screen. I just for the life of me can't seem to flip to the alternate. And I don't know if it's the MK1, the ROM I burned or me just not doing it right.

User avatar
Zippy Zapp
CA, USA

Posted Thu Oct 14, 2021 8:19 am

Ah I see. If you have the BIN file, email it to me and I will burn it and try it on my MK1 and see if I get the same results.

It could be the EPROM or the bin or something else. It is hard to tell without checking.

User avatar
intric8
Seattle, WA, USA
Website

Posted Thu Oct 14, 2021 8:23 am

Fantastic - will do!

FWIW I used this brand new EPROM and it seemed to work beautifully.

User avatar
Zippy Zapp
CA, USA

Posted Thu Oct 14, 2021 10:45 am

intric8 wrote:
Thu Oct 14, 2021 8:23 am
FWIW I used this brand new EPROM and it seemed to work beautifully.
That should work. It is a One Time Program so you can't erase it and try again but still should be fine I have used plenty of OTPs.

I'll try it when I get home, early afternoon.

User avatar
Zippy Zapp
CA, USA

Posted Thu Oct 14, 2021 4:09 pm

Ok so I tested out the ROM file you sent me and it does bootup to the default CBM KERNAL. That said, I couldn't get it to switch KERNALs by holding down the RESTORE key. Nothing happens.

I did get it to change by holding down RUN/STOP + RESTORE and releasing after 5 seconds or so. It didn't reset to Bootup screen but it switched the colors to black screen + white text and a Ready prompt. I then hit Reset button and it did reset to JiffyDos. I couldn't get it to go back to the C64 KERNAL though it would just lockup.

I then put my original ROM back in that came with it and apparently this feature is broken because it doesn't work with the default ROM either. If it worked then I would expect it to reset by holding RESTORE as it does so after switching KERNALs. It doesn't do anything.

Have you looked at the iComp forums? Perhaps there is an answer there. I will check it out because that is annoying.

User avatar
intric8
Seattle, WA, USA
Website

Posted Thu Oct 14, 2021 4:14 pm

I then put my original ROM back in that came with it and apparently this feature is broken because it doesn't work with the default ROM either.
It's not broken. The original ROM that shipped with the board has 2 identical default CBM kernals installed. So you might be switching and not even realize it because they are the same.

I just held down RUN/STOP + RESTORE and nothing happened. So, you at least have gotten further than I have.

You at least can get to my custom color palette I created, and ultimately my licensed JD kernal! Arg, I'd be willing to deal with the janky process if mine did what yours is doing.

User avatar
intric8
Seattle, WA, USA
Website

Posted Thu Oct 14, 2021 4:44 pm

Talking it over with a friend who looked at my files and said all looked well, I wonder if it could be some sort of Jumper thing I need to do? Weirdness...

User avatar
Zippy Zapp
CA, USA

Posted Thu Oct 14, 2021 4:46 pm

intric8 wrote:
Thu Oct 14, 2021 4:14 pm
It's not broken. The original ROM that shipped with the board has 2 identical default CBM kernals installed. So you might be switching and not even realize it because they are the same.
Maybe its not broken but it does not appear to do anything. If I understand the process if my screen is black and text is yellow and I switch to the other KERNAL then I would expect it to reset and see the startup screen of the other KERNAL. In this case it is just a dup of the original. But wouldn't the colors be reset and the bootup screen be shown? I guess that is the part I am unsure of because it isn't working. I am going to try to make my own compilation real quick.
I just held down RUN/STOP + RESTORE and nothing happened. So, you at least have gotten further than I have.

You at least can get to my custom color palette I created, and ultimately my licensed JD kernal! Arg, I'd be willing to deal with the janky process if mine did what yours is doing.
LOL. Yeah I haven't got it down to a science yet it is still janky. I am going to try to post a message on the forums and see what is up.





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