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Questions tagged [commodore-64]

For questions about the different versions and products of the Commodore 64

99
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2answers
17k views

How did Commodore's anti-Microsoft Easter Egg work?

A couple years ago the Toronto PET Users Group published an article (The Great Commodore/Microsoft Easter Egg War, on p. 7) about a newly discovered anti-Microsoft Easter Egg that Commodore hid in the ...
47
votes
2answers
9k views

Why did Commodore fill their power supplies with epoxy?

If you know anything about the Commodore 64 (and other Commodores, really) you know that Commodore really went the cheap route and produced some awful power supplies. The Commodore 128 PSU isn't ...
37
votes
4answers
15k views

Commodore 64 to modern TV

I've been thinking about getting a Commodore 64 machine. However, I realise there's obviously no video cables I have that will work. But when I looked online there are many people using S-Video to VGA ...
36
votes
5answers
5k views

Why do programmable sound generators like SID include a noise generator?

In layman's terms, please explain the reason that all the popular PSG's used in 1980s computers and game consoles provided an additional channel to generate programmable "noise". How was this "noise" ...
32
votes
7answers
9k views

Why did Commodore 64 cartridge games disappear?

The Commodore 64 has a cartridge slot, but by the mid-eighties, cartridge games disappeared; everything was on tape or disk. Why? One answer that suggests itself is that by that time, a larger ...
29
votes
6answers
905 views

Dumping and archiving C64 disks

Doing spring cleaning with family, I found some old C64 disks. These are really old and no one knows what to do with them. Archiving or dumping them seems to be options but we are unsure how to do so ...
27
votes
2answers
1k views

Why does the C64's LIST command choke on REM statements with a Shift+L?

On the Commodore 64 and VIC-20, the LIST command will abort with a ?SYNTAX ERROR on any line that contains a REM statement with a Shift+L character. A minimal program triggering the error would look ...
27
votes
2answers
3k views

C64: Why is POS(π) faster than POS(0)?

According to this article: german C64 Wiki article about the POS() command POS(π) is 20 % faster. Although in my experience it is ...
25
votes
3answers
1k views

What are the differences between a PAL and NTSC C64?

A lot of programs released for the Commodore 64 contained different software for the PAL or NTSC computer. Why did they have different versions of the hardware? Did the software have to be different ...
22
votes
1answer
4k views

Why do all the Speech Synthesizers have that same Voice?

The first time I ever played with software speech synthesis on a microcomputer (not hardware synthesis, like in TI's Speak & Spell) was around 1983, using S.A.M for the Commodore 64. A year later,...
22
votes
2answers
1k views

Why does waggling the joystick of a C64 cause errors loading from tape?

When loading a game from the tape drive on a C64, if you wiggle the joystick around too much the program will not load correctly. Is there an explanation for this? EDIT: Perhaps someone can try to ...
21
votes
3answers
2k views

How can I overclock my Commodore 64?

My Commodore 64 is running quite slow, and my friends want it to be faster, thus overclocking it. But no one knows exactly how to do that. With our current "modern" stuff, nothing seems to help my ...
20
votes
3answers
2k views

What was the purpose and history of the C64's special keys?

I never had a Commodore 64 but I've always been curious what the purpose and history of some of the special keys were. In particular: C= Run/Stop Clr/Home Restore I'm mostly used to the standard ...
19
votes
5answers
2k views

How can I power a C64?

I was chatting with our neighbor and after some long talking, I found out that he has a Commodore 64. I'd love to test it, however I'm not sure how to power it. How can I power a C64?
19
votes
3answers
2k views

How was digital sound playback achieved on the Commodore 64?

The Commodore 64 did not have any hardware dedicated to digital audio playback, so how were some games and songs able to achieve this on an unmodified and unextended Commodore 64? Did these ...
19
votes
2answers
2k views

How did the “rub joystick port to continue” in the Creatures 2 infinite lives cheat work?

The game Creatures 2 on the Commodore 64 had an unusual cheat to get infinite lives which unlike most things on the Internet that are said to "really work" really worked! What you had to do was lick ...
19
votes
1answer
573 views

When does the VIC-II read the sprite data?

This question is about the Commodore 64 and its graphics chip, the VIC-II. Imagine that on a particular scanline, the VIC-II needs to fetch 40 bytes (the background tiles) and since it's a badline ...
17
votes
4answers
1k views

Emulate smooth scrolling

One thing I really liked about the 8-bit (and even most 16-bit) games was that the frame rate was fixed to the vertical blanking. Games were smooth back then. I've been trying to recreate that feeling ...
17
votes
2answers
587 views

What's a good way to implement this “splashing water” effect on the C64?

This pillow fighting game set in Venice depicts the two opponents fighting on a wobbly gondola on a canal. It was apparently known as "Pillow Fight" in English and as "Kissenschlacht" in German, and ...
17
votes
1answer
615 views

How to move sprites to the border on c64?

As far as I know, there is no register in the VIC-II, which would enable this. Despite that, in nearly all intros and in many cases even in old games, sprites on the border were visible. Actually, it ...
17
votes
1answer
1k views

How to check the C64 graphics mode used by Maniac Mansion

I have been investigating the MS-DOS port of the C64's Maniac Mansion game. The original MS-DOS port used the C64-specific character map to draw the various backgrounds in the game. I noticed that ...
16
votes
9answers
4k views

Did early assembly games use hardcoded memory locations?

In the era of C64, Apple][ GS, and SNES, did the games use hardcoded memory locations, or did they let the assembler help them (like modern assemblers)? If yes, how did they manage the memory?
16
votes
4answers
1k views

What graphical effects can be created by changing the VIC-II settings?

I read in this answer that one could create graphics effects outside the usual specifications of the hardware by changing the settings of the machine's VIC-II at specific cycles during the video ...
16
votes
1answer
1k views

How did the Epyx Fast Load cart work with a Commdore 64?

Why would adding a cart in your system suddenly speed up the C64 or the 1541 for loading games?
15
votes
3answers
2k views

6510 clock rate of C64: Why was it considerably slower than the 6502 of the Atari 800?

According to Wikipedia, the Atari 8 bit series had a 6502 running at ~1.8 MHz. Why was the clock speed of the 6510 for the C64, which was designed a couple of years later, considerable slower? Was the ...
15
votes
1answer
298 views

How to create a switchless multi-system 2 button Atari joystick?

All systems that use the Atari 9 pin joystick standard make use of the following pins in consistent ways, with each direction and the fire button being connected to the ground pin when pushed. 1 - up ...
14
votes
2answers
5k views

Install Commodore 64 on VirtualBox

I have installed MS-DOS, FreeDOS and Windows 98 in Oracle VirtualBox. I want to try Commodore 64. How do I install a Commodore 64 emulator in VirtualBox?
14
votes
3answers
859 views

What is the history of DE-9 joystick ports?

The Commodore 64 and the Atari 2600 had compatible joystick ports. Commodore, Atari, and third-party companies like Wico made joysticks supporting that standard. Did this standard have a name? ...
14
votes
3answers
956 views

How do you recognize an early production model Commodore 64?

The Commodore 64 was the most popular single retro-computer produced, probably selling something like 15 million units. Clearly, the C64 is not "rare", but early revisions from 1982 are highly prized ...
14
votes
3answers
775 views

Obscure uses of the Commodore 8050/1541 disk drive

When I was working for a foundry consultancy, we did the following Download routines to add delays when writing certain tracks. This was a security feature. When the program started, it would try ...
14
votes
2answers
2k views

Is the s-video output on the Commodore 64 different from “normal” s-video?

I saw Commodore 64 to modern TV about how to connect the Commodore 64 to a modern TV. I don't understand all the details of the answer, so I wanted to try and ask something specific here. In short, I ...
14
votes
2answers
1k views

What is the “standard” way to implement KERNAL hooks on the C64?

The C64 kernel (or KERNAL as it’s known in the C64 community) routines work via a jump vector table stored in page $03xx. A common programming paradigm to create something like a "device driver" would ...
13
votes
2answers
2k views

How does the Commodore 64 address more than 64 kilobytes of memory?

So, the Commodore 64 has two special registers in locations $00 and $01. By writing to these registers, you can somehow turn on and off the ROMs and other things. The thing that I am not understanding ...
13
votes
2answers
455 views

What was the end of line convention for text files on the 8-bit Commodores

A two part question: Did an agreed upon convention for end of line (EOL) within text files exist on the 8-bit Commodores? If there was a convention, what was it?
13
votes
2answers
366 views

Can a Commodore 64 use two screenmodes on one scanline?

Many games, for example, Maniac Mansion, or Kissenschlacht, use two screenmodes. Oftentimes, a bitmap mode for the main screen, and a text mode for the lower part which displays scores or whatever. ...
13
votes
1answer
511 views

Any difference between a VIC-1541 and a C64-1541?

I have both a beige VIC-20 styled VIC-1541 disk drive and the later brown C64 1541 drive. Is there a difference between them (besides how they look)?
13
votes
1answer
268 views

C-64 Exchange News Service

I am trying to recall the name of a peripheral I use to have for my C64 in the 1980s. I believe it was called Exchange or X-Change. You hooked it up to your cable TV service and it would decode a ...
12
votes
4answers
692 views

How to use BASIC after “LOAD ”$",8 on the C64

After loading a file list from a floppy disk it is hard to program in BASIC because the file list is interpreted as BASIC lines. For example there can be 20 lines with the number 1, because 20 files ...
12
votes
2answers
554 views

Why was BASIC on the Commodore 64 one byte shy of 38KiB?

When you power up a Commodore 64 you are greeted with a friendly message telling the user it has 38911 BASIC bytes free. 38,911 is one byte shy of a 38 KiB (1,024 * 38 = 38,912). What was the reason ...
12
votes
3answers
2k views

What's a good way to implement this “fade” effect on C64

See the beginning of https://www.youtube.com/watch?v=hmfLBAtGAKk. Here's a screenshot: It basically clears characters pixel by pixel both horizontally and vertically. Use sprites for the pixel by ...
12
votes
1answer
927 views

Amount of Transistors in the C64

How many transistors are there approximately in the C64 if we consider every chip on it? I think that it is something around 50.000 but I'm not sure.
12
votes
1answer
738 views

How to avoid sprites confusing the raster timings on C64?

This relates to another question about moving sprites to the border. On my experience, sprites confuse the raster timings very badly. I found this especially problematic, if sprites were moved to the ...
12
votes
1answer
710 views

Why does the C64 have the following palette?

The Commodore 64 has the following fixed palette of 16 colours: (Your palette may vary due to tuning of screen, etc.) What was the reason for this selection of colours? Are these colours ...
12
votes
1answer
500 views

Why was the audio output of the SID6581 so variable between chips?

Each of the SID6581s I have tested sound different, particularly when it comes to filter cutoffs and distortion. What are the causes of these variances?
11
votes
4answers
505 views

Is there software that will run across multiple Commodore 8-bit machines without modification?

I noticed in some of the answers in this question that the Commodore 8-bit line apparently used a jump table at $03xx for entry into the kernel ("kernal" for the pedantic) routines. Figuring that the ...
11
votes
2answers
771 views

Does the Commodore 64 have the PHX opcode?

Code written for the Commodore 64 sometimes uses the PHX opcode, which should push X onto the stack. There also are plx, phy, ply. These were apparently added on the CMOS versions of the 6502; very ...
11
votes
2answers
480 views

What were the 9 VAC pins used for on the Commodore 64 User Port?

I read that pins 10 and 11 are the 9V AC +/- pins on the Commodore 64 User Port. Pin 10 is the + phase while pin 11 is the - phase. I realize the User Port wasn't as versatile as the Expansion Port (...
11
votes
3answers
1k views

What is the name of the back arrow key on C64 keyboard?

What is the name of the back arrow key on top left corner of the C64 Keyboard? Is it escape or back? Also I don't recall using this key. What was the intended usage of it?
11
votes
1answer
311 views

Sprites not rendering correctly before $2000

I am currently testing out some stuff in assembly with C64Studio and Vice and I noticed something with odd sprites. My code starts at $1000 and my sprites at $2000 but when I try to lower the first ...
11
votes
2answers
450 views

How can you tell if JiffyDOS is installed on a drive without opening it?

Is it possible (and if so, how) to tell if a drive has JiffyDOS installed without opening it and looking for the chip?