Questions tagged [commodore-64]
For questions about the different versions and products of the Commodore 64
219
questions
10
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4answers
1k views
Is it possible to just construct a simple cable serial↔︎serial and send data from PC to C64?
I recently saw a video made by the famous "The 8 Bit Guy" about PE6502 computer. At 19:41, he successfully sent a text file from his Windows 95 laptop to the PE6502 using only a standard ...
7
votes
1answer
207 views
Is there a possibility for a user-defined IRQ hardware vector on a Commodore 128 in C128 mode?
When an IRQ occurs, the 6502 microprocessor and its derivatives in the C64 and C128 push the status register to the stack and then load the contents of a two-byte vector at memory address $FFFE/$FFFF ...
5
votes
1answer
153 views
Menu in Octapolis
I have been retrogaming with Octapolis on an emulated Commodore 64. Starting up the game presents a menu offering a choice between one or two players, and between music and sound effects. But I don't ...
0
votes
1answer
94 views
VICE loads files slowly on Fedora 32 Linux [closed]
I lately wanted to try some of the Commodore 64 games I have kept as D64 files on my Fedora Linux system using VICE. I have lately upgraded the system from Fedora 26 to Fedora 32.
After I started up ...
9
votes
2answers
2k views
Why does the VIC-II duplicate its registers? (C64)
After sporadically reading about the C64 and tinkering here and there for over 32 years I finally decided to get to know my C64 memory layout properly. In doing so I have a question about the VIC-II ...
4
votes
1answer
158 views
From what errors could Commodore's tape loader recover
The Commodore PET/VIC-20/C64 tape routines write out the leader for each file twice, and then write the data twice. While it would seem that this should allow data to be loaded more reliably, ...
31
votes
11answers
10k views
Did computer games for Commodore 64 really take “25 minutes” to load “if everything went alright”?
In the Swedish-language song "Nostalgi" by Markoolio from 2003, some of the lyrics go:
My first computer had 64 kB
you surfed on the water, and that's that
The computer games were loaded ...
3
votes
1answer
162 views
Commodore 64 CC65 - I need help with config set up for using a data segment in Bank 3
I'm developing a game for C64 using CC65 to compile my C code to ASM. To get started quickly, I have been defining the data for my sprites in C arrays and then copying the data in those arrays to the ...
4
votes
1answer
218 views
Does a defacto format exist for Commodore 64 SID music?
I first learned about tracker / mod music on my Amiga in the early 1990's. I remember fooling around with Protracker, listening to mods with Intuitracker, and coming to the realization that all those ...
10
votes
1answer
255 views
Rationale for almost heatsunk TO-220 packages on C64 motherboard
The TO-220 packaged VR1 regulator and Q1 transistor in the Commodore 64 motherboard (reference designators cited here from the Rev. B breadbin) are mounted in a way that suggests they were supposed to ...
0
votes
2answers
237 views
Behaviour of commas in PRINT at a line-end
Does anyone have actual documentation on how MS/Commodore BASIC handles line wrapping in PRINT statements?
I tried this in an online emulator:
PRINT 1,2,3,4,5,6,7,8,9,0
In this case it wraps at the ...
10
votes
2answers
673 views
What pointing devices were available for C64/C128?
Apart from 1351 mouse what other official Commodore C64/C128 pointing devices were available, or notable 3rd party like Mouse Cheese. Joysticks and controllers are out of question. C64-wiki seems to ...
4
votes
2answers
653 views
Transforming a memory dump into something loadable
As a follow-up to this question, I now have:
A memory dump of the unpacked application
The start address of the application
I can verify that the dump is correct by starting a new instance of Vice, ...
6
votes
1answer
245 views
Reconstructing uncompressed program from compressed tape image
I have a C64 program in a .t64 file. If I load it into an emulator, what I see is that it loads into a cracktro, which then proceeds to uncompress (taking several seconds at 100% speed) the original ...
5
votes
1answer
166 views
Could a double-sided Commodore disk be written to be used as a “flippy” on a 1541, without requiring flipping on a 1571?
Although the 1571 is capable of reading and writing both sides of a disk, accesses to the second side using the second head will be performed with the drive spinning in opposite direction from how it ...
10
votes
1answer
584 views
Is it possible to boot C64/C128 from floppy
When powered on 1541 reads the disk for a brief moment. Is it used to boot system from floppy? Is it possible to create a bootable commodore 64 floppy?
3
votes
2answers
339 views
How were games and programs written for the C64 in assembler in the 80s? [duplicate]
Were developers using monitors like e.g. "Supermon+64", "Merlin 64" or "Monitor$C000" and cartridges like "Final Cartridge", "Action Replay" (both of ...
4
votes
2answers
171 views
Joystick adapter from 9-pin to USB
I have still a couple of old C64/Amiga joysticks and I'd like to use them on the New C64, which has USB ports.
Is there an adapter from 9-pin male to USB?
This 3-year old article references a company ...
3
votes
2answers
139 views
Is there a Commodore 64 Fastloader/Fastsaver combination that is SD2IEC-compatible?
There exist many fastloading systems for the Commdore 64/VC 1541 combination. Unfortunately, only a few work with the cost-efficient SD2IEC device, a most notable exception is the Dreamload loader ...
1
vote
0answers
63 views
Expansion Port & Final Cartridge et al - Are they just programs in ROM, or is there more to it? [duplicate]
For the C64, there are a lot of emulation devices floating on (Euro) ebay that allow you to load programs from SDcard via emulated serial floppy or/and tape interfaces, simulating the insertion of a ...
20
votes
5answers
3k views
What kind of television set would work with the Commodore 64?
I found out all my SmartTVs don't work because they are too modern for my old computer.
I am a young owner of a Commodore 64, so please bear with me as this machine is a decade older than me.
I do ...
0
votes
1answer
118 views
Any Public Videos of Anyone Playing Jupiter Mission 1999?
When I was growing up, I played a game for the Atari 800 entitled "Jupiter Mission 1999", which has as a premise that you wake up in the middle of the night with astronauts at your door and ...
5
votes
1answer
220 views
Why are the CBM control codes for color setting so spread out?
The control codes (my C64 handbook actually calls them ASCII codes) for color changing on the Commodore 64 are as follows:
Color Control Code Color number
BLACK $90 0
...
3
votes
2answers
232 views
Is there a way to blank out a portion of a screen on Commdore C64?
I would like to blank out a couple of lines between two given rasterlines. Above that I'm planning to have a scrolling background and sprites, below that is a textual info area.
I'm thinking of a ...
15
votes
3answers
2k views
C64/PETSCII block graphic symbol: was there ever a logical reason for their “ASCII” codes?
You know those block graphic symbols that allows you to draw lines, corners, intersections, fine bar charts, etc. they are useful and one can do a lot of stuff, but their code arrangements always ...
8
votes
2answers
211 views
(Lack of) identifying IRQ sources in C64 interrupt handlers
I'm trying to learn about C64 interrupt handling (with the goal of putting it in practice). My understanding is that interrupts can be triggered by different sources but there is only one interrupt ...
3
votes
2answers
162 views
Printing German umlauts with cc65
I want to print German texts with umlauts with a compiled C program on the C64. I'm aware that these characters are not in the charset and that I will have to change the character set.
However, it ...
16
votes
2answers
2k views
Is there a Commodore 64 emulator that can profile running code?
I am developing some software for the Commodore 64, and I am concerned about its runspeed.
Is there an emulator that can report, after running my code, where exactly it spent most of its time? I'm ...
4
votes
3answers
1k views
What are D64, T64, D71 and D81 files?
The docs for the Ultimate-II+ expansion cartridge for the Commodore 64 state:
It is able to read D64 files, as well as D71 and D81 files (no partitions), T64 files.
So what are D64, T64, D71 and ...
15
votes
2answers
3k views
How do C64 cartridges swap running programs without losing state and context?
I recently picked up a 1541 Ultimate II+ for my Commodore 64 and have been amazed at how this device seemingly can do every flash memory and other enhancement feature for the machine, short of CPU ...
2
votes
1answer
176 views
What is the file that VICE refers to as dos1541?
VICE needs a file called dos1541 if you want hardware emulation of the 1541 disk drive. What does that file contain, exactly? The 1541 seems to have two ROMs: a DOS and a KERNAL. But if I take the ...
3
votes
1answer
86 views
How to pass a value to an inline assembler script in a #define macro in cc65
I'm trying to add a compact #define macro in a cc65 program for performing various low-level tasks efficiently. For some of the macros, I need to pass a non-constant value to the assembler part. I ...
3
votes
1answer
256 views
Commodore 64 board dimensions
What are the dimensions of the C64 motherboard? I am specifically asking this because I am considering using a 64C case (these still seem to be in production) for an 8-bit homebrew machine. I wonder ...
1
vote
0answers
184 views
Thinking through the design of a TTL video card: what memory chips and how to manage memory? [closed]
Inspired by Ben Eater's "Let's build a video card" aka "World's worst video card" two part projects on YouTube, I was inspired to consider designing a display adapter for my passive backplane TTL mini-...
0
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0answers
70 views
Composite video from C64 not being picked up by a modern Smart TV [duplicate]
I've purchased a Commodore 64 "as-is" from eBay. I tediously cleaned out the interior and removed all chips and dusted them out and put them back together.
Still, no signal. Except for sound.
So, I ...
1
vote
1answer
263 views
How can I link a BASIC program with BASIC 3.5 for C64?
In the magazine 64er from June 1990 a BASIC extension for running Commodore Basic V3.5 on the C64 was presented. The extension is available at csdb. However, to run a BASIC 3.5 program, it is ...
10
votes
1answer
836 views
Why did the C64 use a separate “CAN” +5 V power supply for some chips?
The Commodore 64 had two separate +5 V power supplies: one
supplied by the external PSU brick and a second one generated on-board
from the 9 VAC via a 7805 regulator. This second +5 V power supply was
...
23
votes
3answers
4k views
Could you manually eject a floppy quick enough to prevent data loss?
I have the vague recollection of "Panic Ejecting" floppy disks by lifting the latch on the drive after immediately regretting a command I had typed. At the time, I was young, impulsive, and blessed ...
13
votes
2answers
322 views
Was the Commodore 128 movable zero page / stack and second block of color RAM actually used?
The Commodore 128 hardware allowed two things that weren't possible on the C64: Moving the 6502 zero page and 6502 stack to another place in RAM besides pages 0 and 1, and switching the CPU and/or the ...
8
votes
2answers
765 views
What does Shift-RETURN do on Commodore's 8-bit computers?
Someone recently commented that, "a shift-Return is really different from a normal one. It moves the cursor to the next line, but does not complete an input operation."
This would be interesting and ...
13
votes
2answers
3k views
How did I fry my SID chip?
I recently got a SID chip (8580r5) for $35 and got it playing music. I was really happy about it. I hooked up a small amp chip to the 9V supply momentarily (it didn't work, I was building that part of ...
8
votes
3answers
652 views
What are my options for fast bidirectional transfer between a C64 and a 1541?
Since asking a similar question, which is really exclusively about using KERNAL to transfer between disk drive and computer, comments, answers and others hint at the fact that using the KERNAL really ...
10
votes
1answer
1k views
How fast are transfers between the C64 and the 1541 floppy drive?
I am developing some software for the Commodore 64, and my intention is to use the 1541 as a coprocessor. I'll have the 1541 compute some data for me, and then retrieve this data over the serial line.
...
14
votes
2answers
2k views
How was a line of Commodore 64 BASIC code stored in its memory?
I am reading up on old C64 stuff and I am using the Vice emulator to play with it. Currently I am studying about how the C64 stored BASIC programs in RAM.
This is quite clear (it starts on address $...
18
votes
3answers
4k views
Are pixels on the Commodore 64 square?
Are "tile pixels" the same size as "sprite pixels", and are they both square (ignoring the rule that multicolor sprites can only be colored in groups of two pixels)?
By "square" I mean that the ...
3
votes
0answers
105 views
Commodore tape drive performance specs
Over the years during which Commodore sold tape drives, there have been a few different versions of the drive with different analog electronics. I'm interested in experimenting with "turbo" tape ...
8
votes
4answers
620 views
How do you play “The Sentinel”?
Many, many years ago, we had a game for the Commodore 64 called "The Sentinel". I remember reading the instructions and being utterly baffled as to how you actually play the damned thing! Hopefully ...
3
votes
1answer
248 views
The Sentinel (aka The Sentry) on Commodore 64 - why was scrolling so fast?
On the Commodore 64 3D games which use one of the bitmap screen modes were notoriously slow.
However watching a gameplay video of The Sentinel will show that in the first-person view, looking around ...
4
votes
1answer
255 views
What is the largest RAM expansion for Amiga or Commodore? [closed]
What is the largest RAM expansion being manufactured today for Amiga and Commodore 8-bit?
5
votes
4answers
867 views
Is it possible in Commodore BASIC V2.0 to configure the system so that the PRINT command does not update color?
The PRINTcommand in Commodore BASIC V2.0 (the one that runs on the Commodore 64) prints each character to the screen address (which is set by the byte in address 648) as well as putting the current ...
