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Questions tagged [commodore-64]

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

7
votes
2answers
252 views

Behaviour of $D000-$D3FF section on the C64 during bankswitching

My question is about bankswitching behaviour on the Commodore 64. I'm writing a C64 game for a 16kb cartridge with EXROM and GAME pulled low, so the available bankswitching modes are (according to ...
10
votes
1answer
367 views

Go program for the C64

Is there a program for the C64 that plays the game of Go? Progress on go engines has started later than with chess, so maybe there is no C64 Go software from the 80s, but maybe someone has recently ...
6
votes
2answers
648 views

Does anybody remember a database cartridge for the Commodore 64?

Decades ago I bought a database cartridge for my C64. IIRC it was a no-name brand being sold as close-out or from a bargain bin. It may have been the slowest program I ever bought. It wasn't too ...
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 ...
0
votes
2answers
357 views

Commodore 64 Game with Falling Character Scream

I'm trying to remember the name of a Commodore 64 game that had a character in it that would scream when it fell. I found videos of Impossible Mission, but the name doesn't seem right and the sound ...
10
votes
3answers
774 views

Why did blanking of screen on C64 SAM enable better quality speech synthesis?

There's this old piece of software still present in today's Windows called SAM that enabled C64 to speak. I remember that we could choose either screen on and worse speech quality or screen off and ...
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 ...
10
votes
4answers
610 views

Looking for an easy to use Commodore 64 disk/sector editor

First, let me say I understand that 'recommendation style' questions can be very subjective, but I believe there is enough value in a few good beginner resource pointers that others could benefit from ...
10
votes
4answers
757 views

C64 BASIC: How to suppress the '?' sign when using the INPUT command?

When you are getting INPUT in Commodore BASIC it always adds a question mark at the end of the string you want to show. Is there a way to suppress the question mark when using the INPUT command?
9
votes
2answers
481 views

Why does this BASIC program keep restarting?

Here is a BASIC program for the Commodore 64, which should load the LIB file from the disk, and then stop. Yes? 5 PRINT "LOADING..." 10 LOAD "LIB",8,1 20 STOP the LIB file is 102 bytes long and is ...
6
votes
2answers
971 views

C64: Strange Behaviour on Control Port 1

I wrote this little Basic program to get Joystick input from Control Port 1. I know that this method is very strange and is better for keyboard input. 20 get a$ 30 if a$="" then 20 32 b=asc(a$) 33 ...
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 ...
8
votes
1answer
757 views

What is this extra lead in my monitor cable?

I have a breadbox Commodore 64 with a Commodore 1702 monitor. My monitor has three RCA-style inputs on the back: Audio (White) Luma (Yellow) Chroma (Red) I purchased a cable which claims to be an ...
2
votes
2answers
289 views

C64, basic v2, DATA strange behavior

I have the following code line: 0DATA"-+-+-" Here "\" and "/" are the ASC codes 205 and 206. I get a syntax error: ?SYNTAX ERROR IN 0 READY. As I can remember, there was same special in the ...
14
votes
3answers
779 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 ...
11
votes
1answer
316 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 ...
12
votes
4answers
699 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 ...
3
votes
1answer
200 views

Which material was used for the 6502/6510/8500 MOSFETs?

I know that in the 80s, there was a shift from aluminum gate material to polycrystalline silicon. I wonder because the 6502 was released in 1975 and there were a lot of different implementations and ...
6
votes
4answers
613 views

What's a safe and easy way to desolder the CPU from C64?

I have probably broken my CPU by connecting 5 V from Arduino (500 mA) to the SENSE Pin of the Casette Port, So now I wonder what would be the safest way to desolder the processor? I have a cheap ...
3
votes
1answer
404 views

How to develop software for the Commodore 64 with VICE?

I see a very large fan-base and hear a lot (especially here on retrocomputing) about how great the Commodore 64 was. Growing up in the Windows 95/98 era, I seemed to have missed a great era for ...
6
votes
4answers
627 views

A game where you program a robot to fulfill missions

I'm looking for a game. Unfortunately there're only few things I remember: You had a robot. There was no way to steer it manually, so to solve a room, every step to do had to be programmed in advance ...
12
votes
1answer
932 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.
14
votes
3answers
867 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? ...
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 ...
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 ...
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 ...
99
votes
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 ...
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 ...
19
votes
1answer
581 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 ...
7
votes
1answer
308 views

Were 1541s upgraded with more RAM?

Since the Commodore 64 was often used with one or more 1541 drive, and these had CPUs which could run user code, it makes sense to me that these would have been expanded in the day, to have roomier ...
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 ...
11
votes
4answers
506 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 ...
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 ...
8
votes
1answer
387 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 ...
10
votes
1answer
958 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
379 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 ...
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 ...
14
votes
3answers
968 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 ...
11
votes
2answers
481 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 (...
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 ...
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" ...
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
907 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 ...
10
votes
2answers
524 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?
5
votes
1answer
334 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 ...
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 ...
9
votes
6answers
842 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?
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?
13
votes
2answers
457 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?
10
votes
0answers
312 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 ...