Questions tagged [commodore-64]
For questions about the different versions and products of the Commodore 64
285
questions
10
votes
4
answers
2k
views
Assembly delay function for C64
I've written a delay function that simply counts the times the screen raster line reaches a particular value.
// zero page addresses
.const delayFrames = $00fa
.const delayCounter = $00fb
// =...
- 255
3
votes
4
answers
432
views
Looking for old C64 game with "thriller" plot
In the late 80s (1989...) I had a C64, I bought some magazine about videogames.
In one of this I read about a "thriller" game, in which you must discover the assassin in a house, I recall a ...
- 1,205
5
votes
2
answers
316
views
Printing characters not at expected position
Simple program...
10 print chr$(147);chr$(5)
20 poke 53280,4: poke 53281,0
30 y=0 : for x = 1 to 35
40 poke 214,y : print : poke 211,x
50 print chr$(171);chr$(177);chr$(179);
60 next x : print : print
...
- 255
17
votes
3
answers
2k
views
Why was the VIC-II restricted to a hard-coded palette?
The MOS VIC in the VIC-20 and the MOS VIC-II in the C64 were capable of outputting 16 colours drawn from a hard-coded palette.
It's clear that the palette size was fixed at 16 colours as a memory-...
- 6,983
2
votes
1
answer
204
views
How to fix the inaccurate mouse movement in the Eye of the Beholder for C64 under VICE? [closed]
I'm trying to play the C64 and C128 versions of the Eye of the Beholder by using the VICE emulator on Windows 11, but the mouse movement is too inaccurate and it constantly flutters on a moving ...
- 573
5
votes
1
answer
273
views
Why can't the VIC-II handle ECM and Multicolor at once?
On the Commodore 64 there are a few different graphical mode selection bits we can enable. This question is about three of them:
Multicolor mode (hereinafter MCM), where pixels are joined pairwise ...
- 36.6k
13
votes
2
answers
673
views
Why does the FRE() function in CBM BASIC v2 return negative values?
On Commodore machines featuring CBM BASIC v2, the FRE() function to query the amount of memory available to BASIC returns a negative number when the result exceeds 32767 bytes:
This quirk does not ...
- 6,983
5
votes
0
answers
157
views
What percentage of the SID was control versus voices?
I'm interested in specifics of the design and manufacturing of the SID, the sound chip of the Commodore 64.
There is a good die photo here http://www.visual6502.org/images/8580/...
- 55.6k
9
votes
1
answer
411
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 ...
- 1,020
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 ...
- 6,983
2
votes
2
answers
496
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 ...
- 29
12
votes
3
answers
2k
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 ...
- 224
2
votes
2
answers
214
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 ...
- 33
3
votes
1
answer
871
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
137
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 ...
- 365
2
votes
1
answer
327
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
566
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
163
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 ...
- 595
7
votes
1
answer
354
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 ...
- 1,079
8
votes
1
answer
459
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 ...
- 263
17
votes
1
answer
427
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 ...
- 6,983
9
votes
2
answers
1k
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 ...
- 2,554
10
votes
1
answer
256
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 ...
3
votes
1
answer
238
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 ...
- 23.6k
2
votes
1
answer
223
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 ...
- 1,566
2
votes
1
answer
409
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 ...
- 1,205
8
votes
0
answers
322
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 ...
- 1,205
18
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 ...
- 55.6k
6
votes
8
answers
1k
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 ...
- 1,046
8
votes
1
answer
927
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 ...
- 597
17
votes
3
answers
5k
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 ...
- 851
18
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 ...
- 283
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 ...
- 1,693
2
votes
2
answers
341
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 ...
- 1,566
6
votes
2
answers
453
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
274
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 ...
- 1,566
10
votes
1
answer
450
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 ...
- 851
3
votes
1
answer
144
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 ...
- 1,566
4
votes
2
answers
700
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 ...
- 1,566
9
votes
2
answers
1k
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
481
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
1k
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 ...
- 6,983
10
votes
2
answers
2k
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 ...
- 645
5
votes
1
answer
528
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 ...
- 645
19
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. ...
- 59.4k
6
votes
4
answers
833
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 ...
- 4,154
4
votes
2
answers
355
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 ...
- 143
7
votes
3
answers
520
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.
...
- 1,160
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