Questions tagged [commodore-64]

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

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10
votes
1answer
267 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
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2answers
295 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
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2answers
131 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
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2answers
124 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
109 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
213 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
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2answers
205 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
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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 ...
7
votes
2answers
186 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
146 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
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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
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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
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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
145 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
80 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
209 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
160 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
67 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
223 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
776 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 ...
12
votes
2answers
295 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 ...
7
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2answers
747 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
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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
632 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
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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
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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
102 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
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4answers
608 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
237 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
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1answer
246 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
858 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 ...
20
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5answers
6k views

Were the custom chips in the Amiga exploited for their hardware bugs like the ones in the C64 and Atari 8 bit computers were?

Here we are some decades on from the C64, and other 8 bit computers. New ideas that resulted in some new graphics effect or mode seem to happen, though we may be near the end of all that. Took a ...
10
votes
1answer
948 views

What sort of RAM chips did the Commodore 64 use in 1994?

For the first few years after its release in 1982, the Commodore 64 used eight RAM chips of 64kbit each. In the late eighties, it became cheaper to use a pair of 256kbit chips of the 4-bit-wide ...
4
votes
3answers
169 views

ca65 vs tass syntax: converting a hex address to decimal?

Most of the tass example programs start with a header like this, which places BASIC code at the beginning of the file that has an appropriate SYS instruction to run the rest of the application: * ...
5
votes
1answer
198 views

SID, sampled sound and bad lines

The SID could play sampled sound by poking a click into the chip at an appropriate frequency, and some Commodore 64 games like Ghostbusters and Impossible Mission did this (though only for a few ...
2
votes
1answer
177 views

What was the die size of the 6581 SID?

The MOS 6581 SID, the original version of the sound chip in the Commodore 64, was according to Wikipedia, 'produced in 7-micrometer technology to gain a high yield; the state of the art at the time ...
15
votes
1answer
1k views

Can I use all features of a Commodore 1571 external drive from a C64?

I know that the Commodore 1571 drive works perfectly well with a C64, since the 1571 will detect it is connected to a C64, and will enter 1541 emulation mode. After which, the 1571 just behaves as a ...
6
votes
1answer
320 views

Putting code into two different memory areas with cc65/ca65

According to cc65 / ca65 documentation, the .org directive does not affect the placement of the code unlike with other 6502 assemblers. The docs suggest defining a memory segment with the intended ...
5
votes
2answers
960 views

What sort of SBC is in the C64 Maxi?

Curious as to what model SBC this unit is using https://retrogames.biz/thec64 8 bit guys teardown says the internals are 'an ARM computer similar to a Raspberry Pi' https://youtu.be/kxx2F4ffmeE
4
votes
1answer
260 views

SID to WAV converter that exports per channel separately

For a C64 SID project of mine (https://soundcloud.com/c64er) I was using an converter almost 10 years ago, but it is missing now with its name... I researched many sites, but no lucky. Is there any ...
9
votes
1answer
394 views

What is the C64 disk drive “Jiffy” protocol?

There seems to be something called the "Jiffy protocol" used for some fast load systems. I know of the JiffyDOS product, which seems to require replacing ROMs in both the C64 and the drive, but it ...
8
votes
3answers
659 views

Are there any open-source C64 DOS wedges and fast loaders?

The ever-so-popular EPYX Fast Load cartridge for the Commodore 64 included a DOS wedge (adding commands such as $ to list the files on a disk, /filename to load a file and @ to show the disk error ...
9
votes
1answer
357 views

What is the exact bus protocol used by the C64/C128 REU?

The Commodore 64/128 RAM Expansion Units used a DMA controller to move data between the REU's RAM and system RAM (or I/O space). One would set the addreses, length and direction for the transfer (or ...
19
votes
1answer
1k views

How does the C64 get an accurate TOD clock on 50 Hz power?

The C64 has two Time of Day (TOD) clocks, one in each of its 6526 CIA chips U1 and U2. These calculate time based on a 60 Hz or 50 Hz input to the TOD pin (pin 19); the clock input frequency assumed ...
7
votes
2answers
467 views

Get exact position of raster beam on C64/C128

By reading register $D012/$D011 or when pausing the execution of an emulation in VICE starting the monitor and entering io d000, it is possible to get information about the current rasterline. For ...
6
votes
2answers
544 views

Commodore monitor to VGA or HDMI

I have this monitor, which I think is a Commodore 64 monitor. I would like to connect it to a pc. Anyone know how to convert VGA or HDMI to this connector format? I've tried searching, but so far I'...

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