Questions tagged [commodore-64]

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

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8 votes
1 answer
360 views

Are the 16 linear steps of the SID Sustain and Filter Volume/Resonance steps of 6.25 or 6.666666667?

The SID has various registers that are described as 16 linear steps: The Filter Volume, The Filter Resonance, and the Sustain of the voice envelopes. The SUSTAIN levels range from zero to peak ...
  • 617
22 votes
6 answers
3k views

Did home computers have mechanical interfaces to typewriters?

In the April 1985 issue of Ahoy!, a reader asks whether it is possible to hook a conventional typewriter up to his Commodore 64. Surprisingly to me, columnist David Barron answers that such ...
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2 votes
2 answers
272 views

Software to generate C64 BASIC code printing PETSCII art

I am looking for a good toolkit to auto-generate C64 basic code, which eventually prints different PETSCII graphics. I am wondering, if there is a good workflow for this, e.g. using a graphical ...
12 votes
3 answers
1k views

Commodore 64 noises during loops, flash load and others

When I was a child, I had a Commodore 64 always connected to a TV via the RF Out. I remember that when running a BASIC program, there were certain noises to be heard. Especially when a longer FOR loop ...
2 votes
2 answers
187 views

How do I save data from a program with CC65 [closed]

I wanted to have a calculator program be able to save a set of answers on a floppy disk or tape but I have no idea what I should do. I am aware that the "cbm.h" library can be used to load ...
3 votes
1 answer
814 views

Commodore SX-64 White screen

I recently acquired a Commodore SX-64. It powers on, but the CRT just displays a white screen. I dont have a test cartridge yet, not that it would help as thereis no display. I havent tried an ...
  • 371
1 vote
0 answers
117 views

Telnet BBS — server side with Synchronet [closed]

I have restored a Commodore 64 and equipped it with a "WiFi modem", which allows me to connect to Telnet BBS sites over the internet. So far so good for the client side. Server-side, I am ...
  • 355
2 votes
1 answer
300 views

Obtaining a CPU execution trace on a Commodore 64 [closed]

I need to collect the execution trace of all instructions executed by the 6502 on a C64. I tried C64 Debugger, but I couldn't find any option for this. Is it possible to obtain with C64 Debugger? Are ...
  • 311
6 votes
1 answer
421 views

How should I set CCGMS on my Commodore 64 to login to a Linux machine?

I have a Strikelink WiFi modem for the C64 (see here and here) and I can connect to a BBS without issues using CCGMS 2017 v4 and the following settings: Baud = 9600 Modem Type = UP9600 / EZ232 For ...
  • 243
1 vote
1 answer
146 views

How to send and receive messages between modern computer and Commodore 64 via WiFi? [closed]

I want to be able to connect from my Commodore 64 to a Linux Raspberry Pi. The ideal solution would be something like ssh that allows me to use the linux machine using the c64 as a terminal but the ...
  • 243
20 votes
6 answers
3k views

Does lossy audio compression damage datasette data?

I grew up with the C64 and had software on cassette tapes. These days, you can find "backups" of this software all over the internet, even in mp3 format (by recording the audio signal with a ...
7 votes
1 answer
285 views

Are SID Players practically almost full-fledged C64 Emulators?

There are many stand-alone audio players (and plugins for general audio players) out there for many systems that play the music of the Commodore 64 that is famous for its SID chip. I believe many of ...
  • 1,009
8 votes
1 answer
353 views

How does the VIC-II/CPU memory access work on the C64?

As a programmer I knew that on the C64 the CPU got the bus in the high phase of PHI2 and the VIC-II got it in the low phase and also stole extra high phases when required. However, it wasn't until ...
17 votes
1 answer
389 views

Was any commercial end-user software written in PROMAL?

PROMAL is a procedural programming language from the 1980s. Its designer, Systems Management Associates, released compilers for the Commodore 64, Apple II, and IBM PC. The language and development ...
  • 6,212
9 votes
2 answers
880 views

Did Commodore ever produce gray colored Commodore 64?

The Commodore 64 was produced for a 12 years from 1982 to 1994. It had several iterations of case color, keyboard color & keyboard labels, badge etc. Commodore was famous for using whatever parts ...
  • 2,524
10 votes
1 answer
246 views

Commodore / Apple II GEOS Document Cross-Platform Compatibility

As I have never used Graphic Environment Operating System (GEOS) on an Apple II (only I on a Commodore 64), I have always wondered were the documents created (from programs such as GeoWrite and ...
2 votes
1 answer
205 views

Does C64 /DMA assertion immediately disconnect the CPU from the address bus?

I have heard several claims (in the comments on this question and answers) that asserting the D̅M̅A̅ signal on the Commodore C64 cartridge port will immediately take the CPU off the bus by deasserting ...
  • 22.5k
2 votes
1 answer
203 views

Timer B Interrupt occurs only once

I was following this tutorial on Commodore 64 timer interrupts and tried to replicate it (except all I was planning on doing was changing the border color.) I noticed that my interrupt only occurs ...
  • 1,558
0 votes
0 answers
247 views

Identify this old C64 soccer game with "speaker"

In "modern" games (Fifa 98, Fifa 2000, PES, etc) you can hear the speaker talking about the match. This was near impossible in the C64 era, but I remember a soccer game that had a speaker ...
  • 735
5 votes
0 answers
207 views

Identify C64 Game About Firemen

I'm searching for an old game for the C64, it was about a group of firemen. I last played it in the 1989, 32 years ago, so I do not remember it very well. I remember only that the firemen don't want ...
  • 735
17 votes
3 answers
5k views

How did the Commodore 64 show a picture while reading cassette?

I was watching this video just now https://www.youtube.com/watch?v=I0YmJluYb6Q&ab_channel=NostalgiaNerd on things that early home computers displayed on the screen while reading cassettes, and ...
  • 51.3k
6 votes
8 answers
826 views

Would a multi button controller have been possible on the C64?

One thing I felt letdown the C64 for many games was the lack of multiple buttons on the joystick, meaning you had to keep the keyboard nearby, (or by your foot!) So you could press space-bar or ...
  • 1,016
8 votes
1 answer
822 views

Why was Carrier Command for the ZX Spectrum superior to the C64 version?

The ZX Spectrum version of Carrier Command has 3D rendering, while the Commodore 64 version, despite a greater amount of RAM, was inferior in comparison. You open the in-game map and there's Google ...
17 votes
3 answers
4k views

How can I store a machine language program to disk on a C64?

I know I can use LOAD "PROGRAM",8,1 to load a program in a certain spot in memory, using the first two bytes of the file on disk. Now let's say I have used the .MON command on the Final ...
17 votes
3 answers
2k views

6502 ORA not updating the accumulator

Unless I'm reading the manual incorrectly, the following should produce $11 when D404 = $10 (I'm turning on the gate for voice1 which has been previously set to triangle wave %00010000/$10) 00153 ...
  • 273
29 votes
2 answers
4k views

What is the Commodore 64C "France version" and why does it need a beefy resistor?

While perusing the schematics for the Commodore 64C (titled COMMODORE-64 B/NE) I came across a suspicious section of the power supply: The unregulated "9V" is connected to the completely ...
  • 1,696
2 votes
2 answers
336 views

How to properly convert an active-low joystick routine to active-high

My last question wasn't specific enough so I'll rephrase it. I've been having trouble with programming game consoles/computers like Commodore 64 that have active-low joysticks, where the bits are all ...
  • 1,558
6 votes
2 answers
423 views

Flash border color during Kernal LOAD routine

I would like to use the Kernal's LOAD routine to load a file into memory, because that seems to be the easiest way to do it. However, that LOAD call is synchronous in the sense that it returns once ...
  • 2,593
6 votes
1 answer
268 views

Commodore 64 sound seems to freeze at a high pitch if executed too soon after startup

I created this little sound driver for sound effects, it makes a classic "laser beam" sound you would hear in old arcade games. There's just one problem, and it's a bit of a strange one. I ...
  • 1,558
10 votes
1 answer
402 views

Confusion in the VIC-II registers

I am playing with my old C64 and fiddling with with VIC-II registers. I am using the great Programmer's Reference Guide, but there is something I don't quite get. According to the register map, addres ...
3 votes
1 answer
141 views

Spontaneous movement and game crashes from active-low joystick routines [closed]

I've noticed this recurring problem when I'm trying to program joysticks or buttons that are active-low (0 = pressed), like on the Commodore 64 or Game Boy Advance. Regardless of the language or ...
  • 1,558
4 votes
2 answers
607 views

How to wait for vBlank on Commodore 64

I'm not new to 6502 Assembly but I am new to the Commodore 64. I'm used to the NES where you have to write everything yourself, such as the NMI/RESET/IRQ vectors, etc, but from what I understand the ...
  • 1,558
9 votes
2 answers
925 views

How to repeat a string in C64 BASIC V2?

I would like to achieve the following: I ask for a number from the user, run a loop number times, and in each loop run, output the string like this: -STR$ --STR$ ---STR$ ----STR$ -----STR$ I tried to ...
  • 93
6 votes
1 answer
462 views

Is this SpeedDOS chip mounted right in my C64?

I have removed a chip to reseat it, but sadly I forgot how it was placed on my C64 (breadbin). I assume its text should be in the same direction of all the other chips on the board, but now I don't ...
  • 243
24 votes
1 answer
930 views

How did the C64 lockup bug and its workarounds work?

The Commodore 64 suffered from a strange bug that caused it to lock up when typing in the full-screen BASIC editor. To trigger the bug, position the cursor on the last line of the screen, type enough ...
  • 6,212
10 votes
2 answers
1k views

How can I connect my Commodore 64 to an RGB+Sync signal via SCART?

I would like to connect my Commodore 64 to my SCART switcher (Shinybow SB-5525), which is connected to a Sony PVM via RGB+Sync. I bought this cable, only to realize after getting it, it is a composite ...
5 votes
1 answer
414 views

Why is my Commodore 1541-II stuck showing "Searching for $" whilst trying to load the directory?

I have a Commodore 1541-II drive. I bought this drive used (but like new) a year ago and I used it on my Commodore 64 for about 6 months, but I moved and just reconnected it to my Commodore and it no ...
18 votes
1 answer
2k views

What's the deal with Commodore's RESTORE key?

Most early microcomputers provided either a dedicated key (e.g. Apple ][), keyboard combination (e.g. PC clones), or dedicated hardware button (countless examples) to "Reset" the computer. ...
  • 58.5k
6 votes
4 answers
757 views

C128D shorted Composite and Ground

I just did a stupid thing and connected a new cable without inspecting it first. It was from a reputable seller, but has shorted pins 2 and 4. What is the potential damage it could have caused and ...
4 votes
2 answers
313 views

C64 KERNAL Loading into I/O space [duplicate]

On a Commodore 64, if I Load "*",8,1 and the file's address (first two bytes on disk) is $D000, will it load to the RAM under the I/O space? In other words, does the KERNAL loader properly ...
6 votes
3 answers
478 views

New chess engines on retro hardware

Does anyone know of any efforts to write modern chess engines for old hardware? (e.g. C64, A2e?) I'd love to see how a pared-down Stockfish or Leela that could fit in RAM could do rating wise etc. ...
  • 1,150
23 votes
8 answers
4k views

Why did the VIC-20 and C64 have only 22 and 40 columns when the earlier PET had 80 column text?

When I was a kid, the "real" computers in movies looked so cool with that 80-column monochrome green text. My first computer was a VIC-20 and it always felt very "toy-like" to me ...
  • 465
3 votes
1 answer
842 views

Problems Connecting an Arduino Uno to a Commodore 64 Joystick Port

I have made up a DB9 connector with connections to an Arduino. I am using pins 1 to 4 on the connector. On the Arduino I have a small program which writes out a series of digital HIGH signals to the ...
2 votes
0 answers
149 views

Running Codenet on a Commodore 64 Emulator

I finally managed to get basic networking stuff working on VICE, thanks to another thread on Retrocomputing. I'm now wondering how to setup a Codenet server emulation. I was able to identify four ...
  • 191
1 vote
0 answers
79 views

How to Perform RR-Net MK3 Detection on VICE Commodore 64 Emulator?

RR-Net documentation describes a detection algorithm for the MK3 model. The algorithm is supposed to reveal the last four hex digits of the MAC address. According to documentation the MAC address 28:...
  • 191
9 votes
4 answers
1k views

Delay loop in BASIC

Yesterday I was looking for a way to implement a delay loop on the C64. I came across this page: https://www.c64-wiki.com/wiki/TIME At the bottom of the page there is a code fragment that waits for a ...
  • 93
7 votes
2 answers
1k views

Modern heat sinks for Commodore C64/C128

The VIC-II and SID chips in the C64/128 are prone to over-heating and are rather expensive to replace nowadays. Some other ICs in these machines may have the same issue. An unmodified machine includes ...
  • 58.5k
6 votes
1 answer
232 views

Chaining IRQ's with BASIC & Kernal routines turned off

Having disabled BASIC and Kernal routines I set up an IRQ to run the following code when the raster line reaches 200: .irq1 inc 53280 // change border colour // lda #$ff // clear the ...
user avatar
5 votes
4 answers
420 views

Running WarpCopy64 on an emulator

I'm interested in IP networking capabilities of the Commodore 64. I learned there is a tool called WarpCopy64 that can be used to run a simple file server on the Commodore. The server can be accessed ...
  • 191
9 votes
3 answers
934 views

Is it still possible to access a BBS via dial up internet on the C64 (or other retro computers)

I was wondering if it is still possible to access any online BBS using dial up and an 80's era computer. I'm aware that some dial up internet providers still exist (eg Nippy Internet in the UK), but ...
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