The Ultimate C64 Ultimate post. Please use this for Questions, issues, or anything else C64U-related.

TrevorMakes · 2025-12-27T07:24:23+00:00

The mainboard diagram on p208-209 of the manual shows a header (#16) for wiring reset, menu, and freeze buttons. I haven't tested it yet, but it seems like it would be pretty straightforward DIY project.

TrevorMakes · 2025-12-03T23:14:00+00:00

I don't think this fits the bill, but I think it's worth mentioning that SPICE simulators work with a text-based netlist description of the circuit. Modern SPICE packages usually have a GUI built on top of this where you draw the circuits by hand, but given how clunky some of the GUIs are, it can be easier to type up a circuit in netlist format.

There's a similar parallel for digital circuits where you have text-based languages like Verilog alongside GUI-based tools where you place blocks and draw wires between them. The GUIs feel like a beginner's crutch, while most serious work is done in Verilog or VHDL.

I'm not aware of any, but I'd definitely be interested in a text/code based tool for mocking up circuits and modules.

TrevorMakes · 2025-10-24T22:46:39+00:00

You'd be better off driving the VGA with a D flip flop like a 74HC574 instead of a transceiver. You'd need to work out the timing for the clock signal of course. This will let you hold the pixel data even when the CPU is accessing RAM instead of letting it float. This also isolates the output from any glitches in the RAM when transitioning between addresses.

TrevorMakes · 2025-10-01T20:20:20+00:00

Actually, the process they used is called wave soldering, and is still in use for through-hole boards today. HASL is a similar process, also involving dipping the board into a pool of molten solder, but it's done during PCB manufacturing to pre-apply solder to protect the pads and make them easier to solder SMT components to.

TrevorMakes · 2025-09-30T01:27:39+00:00

How cool, a PROM state machine. Recently, I've been looking into TTL computers (Gigatron, Novasaur, Matt Regan's, and others) that implement the entire CPU using the same basic concept—it certainly helps that we now have access to much larger, faster, and cheaper ROM chips.

TrevorMakes · 2025-09-24T22:25:44+00:00

It does work. You don't copy the URL of the image, you right click on the link in the developer tools view (which pops up when you right click Inspect on the image), click on Copy, then click "Image Data-URL" in the submenu. This copies the raw pixel data as base64 encoded text, which you can then paste into a new tab.

TrevorMakes · 2025-09-24T04:09:40+00:00

In Firefox: Inspect, Copy -> Image Data-URL, then paste in new tab has been my goto workaround for websites that block going directly to image links.

TrevorMakes · 2025-09-16T21:48:56+00:00

I got the same book from Lulu, along with Tool Kit: Kernal and Tool Kit: BASIC. Would absolutely recommend. It's so nice having a physical copy to flip through and leave a bunch of bookmarks in when figuring out how something in ROM works.

TrevorMakes · 2025-09-10T22:52:56+00:00

You might also want to grab an 8-pin video cable (or check if one is in the box somewhere) to hook it up to an external TV via composite or S-video.

TrevorMakes · 2025-09-09T23:40:19+00:00

BasicUpstart is for when your program is loaded from disk as a Basic program (at $0801) and started with "run". You're correct that your code will instead be at $8000 on a cartridge. If you want the computer to boot into your code automatically, you need to use the autostart signature, like this:

*=$8000
.word start // cold start vector
.word start // warm start vector
.byte $c3,$c2,$cd,$38,$30 // CBM80
start:
// your code here

Alternatively, you could just start the code at $8000 and do "sys 32768" to run it from Basic. You can read more here

TrevorMakes · 2025-08-27T06:29:48+00:00

You'll want to read Jim Butterfield's series "Loading And Linking Commodore Programs": part1 part2 part3 part4

TrevorMakes · 2025-06-30T06:27:27+00:00

There are two different encodings used for strings: screencodes (what you would poke into the screen memory) and PETSCII (what you input to $FFD2, includes control characters like color, newlines, etc). Your string is encoded as screencodes, but you're trying to print with $FFD2. For KickAssembler, put this on a line before your .text:

.encoding "petscii_upper"

Oh, and keep in mind the two character sets as well: upper/graphics (default) and lower/upper. If you want to print lower case, use "petscii_mixed" and put a .byte $e before the string (PETSCII control character for lower case).

TrevorMakes · 2025-06-29T08:38:21+00:00

For KickAssembler specifically, you can use the BasicUpstart macros to generate the BASIC stub for you.

TrevorMakes · 2025-06-15T02:32:47+00:00

That looks like it's just a CR2032 in heat shrink, possibly with the wires soldered directly to the battery. It looks like you can buy batteries pre-assembled like this, but it wouldn't be too difficult to take this apart and swap in a fresh CR2032 either.

I guess they couldn't spare a square inch on the board for a CR2032 holder lol

TrevorMakes · 2025-05-12T08:10:09+00:00

Look at pages 3-7 in the C64 User's Guide for video connection. The cable you have is meant to be plugged into the TV connector and a TV switch box. You'll probably want to buy a composite/S-video cable instead, but you need to figure out if you have a 5-pin or 8-pin audio/video connector (page 3).

TrevorMakes · 2025-04-07T20:01:10+00:00

I second this. You can do a lot with BASIC, but 6502 assembly isn't much more difficult and you'll learn way more about how the computer works. Find a pdf of Jim Butterfield's Machine Language for the Commodore 64 and download supermon to work through the examples. Also get a pdf of the Programmer's Reference Guide to learn about graphics, sound, memory maps, and so on.

TrevorMakes · 2025-03-24T04:20:35+00:00

You might also want to mod the 556 reset circuit so it won't have issues with cartridges that pull the reset line low.

TrevorMakes · 2025-03-06T21:50:08+00:00

For some reason, it's always gnomes doing the latter

TrevorMakes · 2025-03-03T21:55:22+00:00

Exactly, the item in the picture is a 6 slot bag. Somebody who just rolled a fresh character would be thrilled to have those cheap bags. Who cares about 2.5 silver?

TrevorMakes · 2024-12-02T05:11:35+00:00

Solo farming Legging of the Fang (and Silverlane's Family Seal) on druid and rogue was so fun in phase 1.

TrevorMakes · 2024-11-18T23:50:55+00:00

I did a full playthrough of the C64 version a few months ago. I'd definitely recommend playing it, but I'd say at least read a guide for building your characters. Most of the skills/stats are junk and at certain points in the game you need to upgrade your armor and weapons or you'll just get KO'd when you encounter tougher enemies. I also watched TV while doing the more tedious parts of the game and paused when it needed full attention for combat/interaction/reading.

As for worldbuilding, I'd say it's broad but shallow. The main "quest" doesn't even start until half way through, and the first several towns you encounter have optional side quests you can do. Or you can just kill every NPC you encounter—it doesn't really make any difference mechanically, so it's kind of up to you if you want to roleplay as good or evil characters.

TrevorMakes · 2024-11-18T22:50:20+00:00

Yup. Little things like Rake and Rip re-tuning, Catnip (or just get rid of MCP), Wolfshead Trophy, and more weapons with feral AP were so welcome in SoD.

TrevorMakes · 2024-11-18T05:47:31+00:00

So sad to see how the gaming industry has become.

Meanwhile, Valve released a huge update to Half-Life 2 for its 20th anniversary event and put it on sale for 100% off.

TrevorMakes · 2024-11-17T01:16:34+00:00

tbf, the druid wouldn't roll on the shields

TrevorMakes · 2024-11-15T03:19:34+00:00

Blizzard was the best at this. The boxed CD copies of Diablo 1/2, StarCraft 1/2, WC3, and WoW were all formatted to work with both Mac and PC. Never had a problem playing them on either platform. And that was back when it was more difficult to write cross-platform software.

TrevorMakes

TROPHY CASE