36 votes
Accepted

What was the release date of the MOS 8502?

I just talked to Bil Herd (the designer of the C128 hardware), and he said, "It was made specifically for the C128, design mods done by Dave DiOrio," and so was essentially "released&...
cjs's user avatar
  • 24.7k
21 votes
Accepted

What is this unusual syntax for the Commodore SYS command?

Line 40 looks like a typo. It should be SYS 65493 instead of SYS 65439. SYS 65493 ($FFD5) maps to the internal LOAD routine at $F49E Line 10 calls the filename parsing routine PLSV at $E1D4. PLSV ...
Darren's user avatar
  • 641
14 votes
Accepted

Commodore 64 - any way to safely plug in a cartridge when the power is on?

is there any programmatic setup you could do on a 64 that would make it safe to insert a cartridge with the power on ? This calls for a clear No, But :) Why is it Risky? In general it's unhealthy ...
Raffzahn's user avatar
  • 213k
12 votes

What is this unusual syntax for the Commodore SYS command?

Three related concepts one should understand when trying to understand Commodore BASIC programs (or other Microsoft-derived BASIC interpreters for that matter) are the CHRPTR address, and the CHRGET ...
supercat's user avatar
  • 34.7k
10 votes

Commodore 64 - any way to safely plug in a cartridge when the power is on?

You can not programmatically setup safe insert/remove cartridges. But there are hardware for enabling/disabling cartridge. By disabling a cartridge on startup, one can prevent cartridge software from ...
wizofwor's user avatar
  • 2,728
9 votes

Correct voltages and current draw for Commodore PC-1

Test #6: +5 V 3.5 A (max): 4.96 V (Vpp: 120 mV) +12 V 1.4 A (max): 11.53 V (Vpp: 400 mV) -12 V 200 mA (max): 12.29 V (Vpp: 88 mV) Are these voltages normal? Yes, those voltages are 'normal'. The ...
Bruce Abbott's user avatar
  • 6,635
5 votes

Commodore 64 - any way to safely plug in a cartridge when the power is on?

From my experience back in the day, inserting a cartridge after loading and running a machine language monitor would more often than not disrupt machine operation, but would occasionally work in such ...
supercat's user avatar
  • 34.7k
5 votes

Converting CGA (from Commodore PC40) to RetroTink 5X?

You need a CGA-to-SCART convertor, such as this one you can build yourself or this one you can buy (in Europe). You’ll also need a nine-pin cable with appropriate connectors, such as this one.
Stephen Kitt's user avatar
4 votes

Is there a version of Python that runs on a QL, Speccy or a Commodore?

Officially python was never ported or released on ZX-Spectrum computers, because it was first apperared in February 1991 when most of Speccy publishers moved to another modern hardware platforms. Only ...
Alexander B's user avatar
2 votes

Commodore 64 - any way to safely plug in a cartridge when the power is on?

Working on the assumption that cartridges are basically PCBs. PCBs (and other connectors) can be designed to be hotplugged, and can be recognised as such by having fingers of different lengths such ...
Mark Morgan Lloyd's user avatar
2 votes

What can be done with a USR file on the Commodore 1541 disk drive?

From the DOS point of view USR files are mostly like PRG and SEQ files. There are conventions with PRG and SEQ files, namely that PRG files have a two byte load address as the first to bytes and that ...
BlackJack's user avatar
  • 291
1 vote

Name of Commodore tape format?

How did Commodore call their tape format? Hmm, what's wrong with Tape Format? It must have had a specific name, right? Does it? If you insist, maybe try CTF or 'Commodore (PET) Tape Format'? But ...
Raffzahn's user avatar
  • 213k
1 vote

Commodore PC-1 power supply measurements off

Side note: If anyone reading this wants to re-cap the Commodore PC-1 PSU, I made a BOM, as well as a rough schematic and board layout: github.com/nbolton/cpc1-psu To answer the OP question, I imagine ...
Nick Bolton's user avatar
1 vote

What is the difference between the Commodore 1701 and the 1702?

The 1701/1702 monitors appear to be identical. They share the same Brown Commodore-64 colored case. They both have dual inputs with a switch in back to select between them. However, these monitors ...
Charles L Hawn's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible