Questions tagged [commodore-64]

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

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14
votes
3answers
2k 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 ...
7
votes
2answers
839 views

Creating Null Modem Connection between two C64s?

Trying to establish a null modem connection between 2 C64s using 1 Commodore 1660 300 Baud modem and 1 Commodore 1670 1200 Baud modem. Does anybody have detailed instructions on how to configure the ...
11
votes
1answer
2k views

Why do many JiffyDOS users install a toggle switch to disable it?

For those that don't know, JiffyDOS is a ROM replacement for a Commodore 64 (and 128, I believe) and its 1541 disk drive. This ROM replacement provides OS shortcuts, faster load times, etc. I've ...
8
votes
1answer
508 views

Which memory management is easiest to program - CoCo 3 or C128/Apple //e? [closed]

As the 8-bit systems hit their peak in the mid-1980s, breaking the 64K barrier was all the rage. Commodore, Apple, Atari, and Tandy all shipped new 8-bit machines that came standard with 128K. Of ...
20
votes
3answers
5k 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 ...
14
votes
3answers
3k 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 ...
15
votes
2answers
1k 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 (...
15
votes
3answers
2k 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 ...
39
votes
5answers
6k 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" ...
12
votes
3answers
2k 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
2k views

Which C64 games support two buttons?

CIA 6526 chip used in Commodore 64 is capable of controlling two separate joystick buttons. But the second button should be connected through paddle pot input. This option was not popular till the ...
11
votes
2answers
804 views

Did the ZX Spectrum have more original titles than C64?

From casual reading, it seems as though many C64 titles were ported from the ZX Spectrum. Why was this the case? Was the ZX Spectrum more popular? Or easier to develop for?
6
votes
1answer
396 views

Other than Ocean, what other famous loaders were there? [closed]

Many people are familiar with the awesome Ocean loaders from the 8-bit days. For those that are not, "loaders" are small programs that were usually artwork and music (sometimes games) that were ...
45
votes
4answers
35k 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 ...
12
votes
6answers
2k views

Is there a C64(or any other) emulation that can be run in terminal?

I was looking for a C64 type computer that can be used in the terminal. Can I code one or is there one on the interwebs?
20
votes
12answers
5k 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?
18
votes
2answers
732 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
0answers
433 views

Is there a simple BASIC program that demonstrates SID6581 distortion?

Many songs use a SID6581 design "flaw", distortion, as an effect. I tried experimenting with the filter and resonance registers, but was unable to reproduce the sound. What conditions are necessary ...
15
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 ...
16
votes
2answers
10k 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?
11
votes
3answers
2k views

How do serial (user port) adapters achieve speeds above 1200bps in C64?

The information I have states that the userport' serial speed is about 1200bps, but there are some carts going up to 9600bps. I would imagine that the 1200 is the limit, so I'm wondering how is the ...
8
votes
3answers
797 views

Advantages to installing a parallel port in a C1541-family drive other than speed

Are there any advantages to installing a parallel port in a C1541-family drive and using a parallel cable to a PC to image disks, other than increased speed (i.e. since the standard IEC protocol is ...
10
votes
1answer
407 views

Is there any existing hardware mod for C64 to decouple tape drive from IEC (1581 drive collision)?

Commodore 64 has a known bug which doesn't allow to use tape drive together with a 1581 drive. Basically, in C64 the SRQ (Serial ReQuest) line is connected between IEC bus, CIA chip and the tape ...
10
votes
2answers
958 views

How many IEC devices can I connect to a C64 / C128?

I have two C64's, a C128, and as for drives: SD2IEC, 1541-U2, 1541-II and a 1581 - that makes for 4 devices. Looking at the drives, those only allow 4 device ID settings (8,9,10,11), but according to ...
9
votes
1answer
1k views

PAL C64 in the US - 50Hz vs 60Hz AC Frequency, will that matter?

I currently live in Japan and use PAL C64 from Europe, here the line voltage is 100V at 50Hz (Tokyo). I will be moving to the US in about 2 months. The US uses 110-120V (power supplies are usually ...
16
votes
1answer
611 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?
13
votes
1answer
1k 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 ...
10
votes
3answers
2k views

What Commodore 64 emulator and assembler to use? [closed]

I'm about to do some assembly coding for the C64 but for sanity I would like to do the actual coding on my Mac with an emulator. My question is; which is the most maintained/up-to-date emulator/...
14
votes
2answers
736 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?
17
votes
1answer
2k 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?
22
votes
3answers
4k 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 ...
18
votes
1answer
933 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)?
8
votes
1answer
862 views

Commodore 64 with partly working keyboard

My Commodore 64 has developed a fault with the keyboard. Some of the keys are working and some aren't. As far as I can see there is no pattern and they are randomly distributed across the keyboard. ...
22
votes
5answers
5k 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?
11
votes
1answer
415 views

Differences in disk storage between systems

Coming from the TRS-80/TandyColor Computer lines, I had always heard of how slow some other systems disk storage were, regarding data transfer rates, etc... The CoCo lines disk storage was pretty fast ...
21
votes
3answers
3k 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 ...
11
votes
1answer
550 views

How many analogue RGB signal levels did the VIC-II have?

Although only 16 different colors were allowed on c64 (more exactly, in the VIC-II), which came from a fixed palette, the video output created an analogoue tv signal. Which means, somewhere in the ...
18
votes
1answer
939 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 ...
28
votes
3answers
3k 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 ...
31
votes
6answers
2k 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 ...

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