Questions tagged [commodore-128]
for questions about the Commodore 128 home computer
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Commodore 128 bottom row of keys work with different shift keys
I have been playing with a Commodore 128 that I picked up but I have noticed one, what I would call, weird keyboard problem(?).
If I an on the bottom row of the keyboard every other key works with a ...
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Where to find datasheets for MOS (Commodore) 85xx chips?
It seems difficult to find any detailed technical information online for the 85xx chips used in later Commodore 8-bit computers. For example, there's an excellent archive at http://www.6502.org/...
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Invoke BASIC 7.0 NEW command from C128 Assembly
I want to end a C128 lm program the same way as the BASIC NEW command was executed. I tried to call the known entry point at $51D6 via JSR but is seems to not perform.
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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 ...
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Is there a routine like FETCH, STASH and SWAP for transfering data between memory bank 0 and 1 on the C128?
The BASIC 7.0 of the C128 provides commands for copying a block of bytes between an REU (RAM expansion unit) and memory in Bank 0 or 1. For those who do not own an REU, is there a function for copying ...
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What are these electronic components found inside a Schaffer BV 223-5-04008 PSU for the Commodore 128D?
I'm having a little hard time trying to map some electronic components in a C128D power supply unit. The PSU is the Schaffer BV 223-5-04008 (schematic) provided with the German version of Commodore ...
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3
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Slowdowns in CBM BASICs between 4.x and 7.x?
I recently came across a thread suggesting the versions of CBM BASIC on later machines, I believe the Plus4 and 128 were mentioned, were significantly slower that earlier versions. I haven't found ...
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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 ...
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RGBI to VGA converter [duplicate]
Is there an off the shelf converter / adapter from C128 RGBI to VGA that will work with modern-ish low voltage VGA?
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How do I save Commodore BASIC programs in ASCII?
On the Commodore 128, the built-in BASIC saves programs tokenized. How can I save (and then later load) the programs as ASCII instead?
For example, like the ",A" option in GW-BASIC or the ...
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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 ...
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Can the 80-column display really be improved on a C128 and 1902A monitor?
The March 1988 issue of RUN contains the following tip from a reader on page 20:
Attention: C-128/1902A Owners!
If you use a Commodore 1902A video monitor with your C-128, here's a way to get a ...
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What is the largest single file that can be loaded into a Commodore C128?
What is the largest single file that can be loaded into a C128 using standard Kernal functions (i.e., LOAD, DLOAD, BLOAD). Is it possible to load more than 64kB by overflowing to Bank 1?
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Extending C128D Keyboard cable
I need to make a 25 pin Sub-D extension cable for my C128D keyboard. I think it may be as easy as connecting male pins from one side to corresponding female pins on the other side, but need ...
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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 ...
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How can I restore the VDC RAM to usable text mode after clearing memory for hi-res graphics?
So, I've got a C-128 with only 16K of VDC video RAM. I've finished my lovely high-resolution graphics routine on the RGBI display and want to exit to BASIC with a functional 80-column text screen, ...
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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 ...
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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 ...
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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?
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Was Commodore 128 ever used in business environment on a mass scale?
Commodore 128 / 128D was capable of displaying 80 columns through RGBi, therefore it could compete with other business machines of the time, but was this the case? Was this line of machines ever used ...
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Did the Commodore 128's Z80 CPU also have full access to the machine's custom hardware?
The C128 was a C64 with an extra CPU as well as extra memory. But the second CPU was a Zilog Z80 while the primary was the usual Commodore CPU, a MOS 6502.
The Z80 was there so that CP/M software ...
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Are there games for the C128 that run (mainly) on the Z80 rather than the 6502?
The Commodore 128 was a version of the Commodore 64 that also had a Z80 CPU along with its "native" 6502 CPU so the system could run CP/M as well as C64 software. (As well as more RAM and ...
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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 ...
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Printing on the graphics screen with lowercase/uppercase letters using CHAR command in Commodore BASIC 7.0
The CHAR command in Commodore BASIC 7.0 on the Commodore 128 allows printing a text at a given position on the screen. Other than the PRINT command, CHAR also works in Hires graphics mode. Since the ...
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Restore a BASIC program after reset or "NEW" command on a Commodore 128
A BASIC program that was deleted with NEW or after a reset can be restored on Commodore computers as long as no new programs are entered or loaded (or the computer is powered off). For the C64, the ...
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Are there Commodore BASIC 7.0 music demos?
Commodore BASIC 7.0 that came with the Commodore 128 provided commands for playing music notes and setting different instruments. The play function even had a feature that played a note in the ...
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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
...
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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 ...
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MOS 8502, just a 6510B?
I'm looking over what little I can find on the 8502, and from what I can see it appears to be a 2 MHz version of the 6510 with an extra I/O pin.
Much ado about the speed, but the Atari's 6502B's were ...
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What was the intention with the Commodore 128?
The Commodore 128 had 2 CPUs, 2 video graphic chips, and 2 I/O systems/chips.
It had 3 modes: Commodore 64 mode, Commodore 128 mode and CP/M. The first shared one of each CPU/chip, the CP/M mode the ...
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How to add Final Cartridge III to VICE C64/128 Emulator
How do I properly add Final Cartridge III to VICE Emulator?
In the file menu, VICE has an item Attach cartridge image... which splits up into CRT Image but also a list of several cartridges, among ...
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Old C128 - normal to straight away pull 2 amps? [closed]
I'm trying to get an old C128 working again. Lacking a C128 power supply, I've attached a C64's power supply's 9VAC and am supplying 5VDC from a bench power supply (with a 2A limit at the moment).
...
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Possible cause for C128 A/V output containing faintly coloured columns and failing shortly after?
I recently acquired a Commodore 128. It worked fine for about an hour, in both C64 and C128 mode, at the exception of some coloured bars, before displaying garbage and not booting anymore into any ...
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Commodore C128 MOS 6526A interchangeability?
I have a working C128 desktop that I'm using to troubleshoot a non-working C128D-CR.
I suspected a problem with CIA 2 on the C128D, so I swapped its chip labelled "6526A" with a 1988 year stamp with ...
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Commodore VIC-20/64/128/16/Plus 4 floppy disk drive replacement
We all know that floppy disks are getting hard to find, and floppy drives are fragile to begin with (especially Commodore's 1541 drive). I know that several companies and parties have released floppy ...
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Getting your Commodore VIC-20, 64 or 128 online
Back in the day, of course we used modems ("dial-up modems" in today's parlance) to get our Commodores connected to other systems.
These days I know several people have concocted options to get ...
- 1,642
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How can I adapt a digital CGA/C128 signal (RGBI DE-9) to a modern monitor?
IBM's CGA and the Commodore 128's RGB video output both use a DE-9 connector. How do I adapt the CGA video output from an IBM XT 5160 or Commodore 128 to a modern monitor?
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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 ...
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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 ...
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What is the proper way to test the PSU output for a Commodore 128D?
This question is directly related to comments on the more general question and answer here.
The Commodore 128D and 128D-CR have an internal PSU that can be readily and safely disconnected from the ...
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What precautions to take when powering on old computer for the first time in years
I have a Commodore 128D that hasn't been powered in about 15 years. I want to begin using it again. It has been stored in cool dry places like attached garages, in a cardboard box.
I hope this ...
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Did C128 native games have any technical advantages over C64 ones?
Over the years I rarely saw anything specifically for the C128 besides CP/M and C-Net 128. I searched at one point for any C128 specific games but only found a version of "The Last V8" which didn't ...
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Why does the Commodore C128 perform poorly when running CP/M?
I have seen several claims of poor performance of the C128 when running CP/M, and would like to better understand these claims, especially in comparison to other CP/M machines of the early to mid-...
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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?
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Can the two CPUs in a Commodore 128 run at the same time?
The Commodore 128 has two CPUs. One is some variant of the 6502, and the other is a Z80.
One CPU is there for compatibility with the Commodore 64 and the other is there presumably to give basic ...
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