Adventures with a C64c

Charlie

.. . Mouse . ..
Joined
Jan 20, 2008
Posts
690
Country
UK
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Wirral
Hello all,
Like Halley's Comet I've been a-journeying through the void and have finally returned to bask in the glory of the bright sun that is AmiBay... let us see if anyone goes "Ooo" when I reveal the full glory of my tail.

On second thoughts one can stretch an analogy too far. I can't imagine many people would be interested in seeing the full glory of my tail-end revealed.

Let's wipe that horrible thought from everyone's mind with some retro p0rn. :D

A good while ago a very nice chap on the forum came to visit and left me with a C64c. Lovely! Now, before getting thoroughly in to 32bit RiscOS machines my 8bit 'life' was spent with the Beeb and later the CPC... both marvelous machines - I still have several.
Two systems I never played with at all were the Atari 800 and C64, never even been in the same room as one! I bought and seriously modded an 800XL a good while ago, as is my want. Lovely machine, if a little built down to a price in places. I suspect I still don't understand 10% of what it can do.

As someone who's not previously touched a C64, but a good many other systems, my initial impression was "Lovely, and I'm so glad I got a C64c. Feels a bit price-engineered". Bread-bin heresy? Maybe, but I never fancied a 'classic' C64 or Vic20. Plug in, switch on... Hmm, not the usual (black and white) start screen, but nice. In spite of a Video-SCART lead I have to say I wasn't at all impressed with the display quality, whiffs of boggo Atari 800 if not quite so bad...

First project:
Can the C64 do better? The SCART lead is wired for composh1te... googling revealed lots of lovely hacks to improve video quality (later) and how to wire SCART for S-Video, which I'll do as soon as I get the right DIN connector. (The Beeb, Atari, CPC compatible spares I have won't fit the '64)

Second project:
One of the reasons I never considered a C64 back in the day (apart from the appalling basic) was it's reputation for fearsomely slow software loading... rather like my rambling on for several hundred words without a single piccie on the Photo Booth forum. Surely not that bad? Well I'd find out, but first I'd need some way to load some applications (games) to properly road test my new baby (games!)
After more googling price vs performance suggested SD2IEC was the way to go. Scitech Supplies LTD do a very nice version - Well made, one of the cheapest, and plug and play which was nice for a newby like me for testing... But a bare board - being a long-term modder it was always going to end up installed inside the computer.

Let's load a few games and play. :D
The good:
Thousands and thousands of games! Many of them very, very good indeed. No wonder the C64 had such a good reputation and lasted so long. I downloaded a pre-made SD2IEC image with a simple loader app from thefuturewas8bit.com which eased my way in nicely.
The bad:
My, my that Basic really is very primitive indeed! Still, Load"*",8 <Return> Run <Return> is all I'm likely to need for this machine. Bit of a (small) bummer that the machine doesn't have a full set of cursor keys.
The very bad:
Ohhhh my god! I had heard the C64 was slow to load stuff, even off floppy, but I really wasn't expecting the full miserable reality of it all. Mind changed - how on earth did the C64 last so long..? How many frustrated owners must have pointed their 44Magnum ("Ok punk, make my day") at their computer and blown it away in frustration, especially as the '64's home was the land of the free.
The ugly (hack):
More googling... Ah, JiffyDOS. You see I really didn't know much about the C64. All hale the great and wonderful developers of JiffyDOS for making an unusably slow machine (slight exaggeration) tolerable.

Third Project:
I need JiffyDOS, I need JiffyDOS, I NEED JIFFYDOS... Further googling found me the required info. Some hackery later and my machine now boots JiffyDOS by default, or with a <Power On>+<Restore> the standard CBM tat.
I must have rambled on for a good few thousand words by now (Where's Bear and Porridge..?). Time overdue for some photos. Apologies for the quality, no idea where family members have stashed any of the proper cameras.


Starting with the SD2IEC mod:

C64c.jpg
-C64c, Moody Lighting-

C64cSD2IEC.jpg
-SD2IEC Slot Round the Back-

GlueSD2IEC.jpgWiringSD2IEC.jpg
-Hot Glue, I Love Hot Glue. And Soldering-

Having sussed the SD2IEC interface I bought by plugging it in with the provided connectors I wanted something neater, something hacky. In short I wanted to apply Dremmel, sandpaper, solder, and hot glue, to make it neater and make it mine.
First I buzzed out the connections while it was all set up, decided where I wanted the interface to be mounted, and then hacked the multicoloured ribbon cable to length before soldering it to some likely points - Note: actually bothering to read up on the subject is for people who aren't in a hurry!
After testing to see if it still worked (yes!) I desoldered the two tact-switches for 'disk change' and 'reset' from the SD2IEC board and mounted some taller ones to the opposite side - the eagle-eyed will have already spotted the plan.
I generally can't be bothered to measure stuff (you should). So by eye I cut and sanded the excess PCB from the SD2IEC board so the SD slot would be flush with the end. I then Dremmeled and sanded a slot in the lip of the upper case so then glued under it the end of the SD card would be just poking out - a cheeky little mini MicroSD adapter suits nicely I feel.
The plan for the buttons was to use a couple of nice silver tact-switch caps to poke through the case for a sympathetic look. The reason for using longer switches was I'd learned my lesson from doing a similar mod for my Atari 800XL - lots of very fine and frustrating Dremmeling, then Supergluing, to make some bespoke switch tops to work with the supplied ones.
At this point I did actually get out a pencil to mark the switch positions then started to 'drill' two holes with the end of a pointed hand file... Why?
While the C64c PCB is nicely made the case is made of very cheap plastic akin to soft cheese. (Atari 800XL is the exact opposite in both respects) I wanted to take it easy for a good result and twisting a hand file was all that was required to go through the plastic!
I then fettled the holes with a screwdriver wrapped in wet 'n dry, and also sanded the inside of the case to get both buttons to stand as I wanted. Then placed the PCB over the top, checked everything worked, and hot glued it in place. "Oh how I love thee, hot glue. But why, oh why, do you burn my fingers so? And why must your gun always do that infuriating dribbly thing?"
Next I offered the lid + SD2IEC up to the base to work out where and how much to Dremmel and sand form that... At which point I found the weird metallic paper that passes for an IR shield in this machine was in the way of the connector - never mind, every cloud: Scissors cut paper. Ah, AND a cap on the PCB was in the way - 'bendy, bendy' and the cap was 'relocated'

All still working? "Yes!"

A result.

The next (less tiresomely long) post will continue the adventure - JiffyDOS modding.

- - - Updated - - -

Part 2:
I may have made some unkind comments about the C64 in my previous post, but rest assured all you zealots that so far I do think it's a great machine. Also I'm very grateful to have it as it was a most kind gift.
:D-My Sincere Thanks-:D

To a large extent an old system's foibles tend to lend it charm where they might be regarded as flaws in a new device - those foibles also hand easy excuses to get one's hands dirty!


Which leads us nicely to JiffyDOS:
Apologies to the many who may (may not!) be reading with wiser heads, I find JiffyDOS to be an incredible feat. Not only does it improve on the sloppy/slow CBM firmware while maintaining an amazing degree of compatibility, but having recently done a bit of reading it goes a long way in circumventing some fundamental design flaws in the C64 when it comes to the (lack of) speed in the serial bus.


Less rambling, more photos:

C64cROM.jpgM27C256.jpg
-Replace CBM ROM with EPROM-

In my case my machine has a 'short board' that combines the 8k kernal with the 8k basic. So if I want to switch between CBM and JiffyDOS mode I need a 32k EPROM to hold: Basic+Kernal+Basic+JiffyDOS. I then need a way to switch between '16k banks' depending on what I want to use.
The ROM is easy enough, even for us 'doze users. Assemble your ROM images in a folder, open a command prompt and issue something like the following command:

copy /b Basic.bin+Kernal.bin+Basic.bin+JiffyDOS.bin 27C256_JiffyDOS.bin

One will then have a suitable image to burn to ROM, in this a 27C256 although a 27512 will be fine - just use the above command to put two 27C256 images together.

74HCT74D.jpgDeadBug.jpg
-How to Make a Switchless Dead Bug-

In a nutshell it's then 'just' a case of plugging in your new ROM in having lifted pin 27 as that will need attaching to some kind of switch to choose between 16k banks. As you will see from the above pictures I did something a bit more sneaky. With the aid of a 74HC74 and holding down the <Restore> key (or not!) on power up I can select my 'OS' without any messy extra switches. The scheme I've gone for is a variation of the idea I found on Pasi Lassila's Blog. I'd say his implementation is less fiddly and, um, 'ghetto'. Mine is less obtrusive when installed and I can more easily pull and reprogram the EPROM should I want to.

SocketC64cROM.jpgInstalledIFFYDOS.jpg
-CBM ROM Out, Socket In, Switchless ROM In-

I happen to prefer turned pin sockets to the wipe type. One will see I removed the center bar from the socket to ensure room for the 74HC74 under the EPROM. Two further slivers of Kynar make the final connections to allow the 'switchless magic to happen. Pin 27 isn't removed, just decorously dangling out of the socket like... so much well turned leg and thigh peeking from under soft Egyptian cotton bed sheets. Ah, um. Moving on...
 
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roy_bates

resistance is futile!
AmiBayer
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looks like a toggle free jiffydos to me bud;)(hold restore on power up)

nice work so far,cant wait for the rest of the pics.
 
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Charlie

.. . Mouse . ..
Joined
Jan 20, 2008
Posts
690
Country
UK
Region
Wirral
Hi Roy, thanks for the kind words.

Last piccies of my baby in action:
ItLivesIFFY.jpgItLivesCDOS.jpgItLivesLaserSquad.jpg
-IFFY-DOS, CBM, and Playing Laser Squad-

All working well with JiffyDOS - I couldn't resist a little hackery before I burned the ROM. (The colours aren't quite true in the photos, rubbish camera) Oh, what a pleasant difference it makes! <Power On>+<Restore> and I have boggo CBM should I ever need it...

...I've always said "The measure of a good 8bit computer is how well does it play Laser Squad?". Actually I pretty sure that's the first time I said it, especially as neither Beeb nor Atari have a version I'm aware of... but the C64 plays a darn good game, if just pipped by the CPC version for top honors.

Time, I think, to spend the rest of the evening playing.
 
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