mos_8502

@mos_8502@soc.studio8502.ca

Retrocomputing Maker and Designer in Ontario, Canada. I make stuff without promising a delivery date. I don't do crowdfunding, but I do gratefully accept Patreon and Ko-Fi support for what I do.

I am also a GNUstep contributor.

Language: English (I do speak others, but not well enough to claim fluency of any real kind)

Pronouns: He/Him

Nationality: Canadian

Politics: Hard Left, New Democratic Party, but pragmatic about it

Technology: Retro

This profile is from a federated server and may be incomplete. Browse more on the original instance.

mos_8502, to random

$41.14USD. That's the BOM cost, in single quantity, from Mouser, for the eight chips which make up the new design. $41.14 in chips to make a computer which is, to be honest, flat out superior in capabilities to the Commander X16, and probably much closer to the design the guy had in mind at first to boot, before too many cooks came into the kitchen and fucked with the broth.

Obviously that BOM cost does not include passives or PCBs. The per-unit BOM price goes down as batch size goes up, too.

mos_8502, to random

Okay. Big old image heavy thread. There will be no alt text, because alt text that accurately describes schematic diagrams would get real repetitive repetitive real real fast fast. Sorry.

Schematic review, a section at a time. Let's start with the CPU. The W65C265S, clocked at 8MHz. I doubt I got anything wrong here. Capacitors are 1%, 0402 SMDs unless otherwise noted. The CPU for this revision is a PLCC84 (SMD socket) because I have a tube full of the things on my desk.

mos_8502, to random

You can, in fact, do DMA through the cartridge port on Sentinel 65X.

Your cartridge needs only pull the BE line low during any period where PHI2 is low -- this will cause the CPU to stop and release the bus until BE is high. You may then use the address and data pins to access whatever you want, except for addresses which select hardware internal to the CPU; the CPU pin which would need to be brought low to write into the CPU is held high by a pullup and not accessible from the cart port.

mos_8502, to random

Disposable products have their appropriate place in the economy. Disabled people often need plastic straws, and shouldn’t feel bad for it. But in most circumstances, outside of medical or accommodative items, there are better choices. Steel or glass straws, industry standard safety razors rather than proprietary disposable cartridge systems, quality used real wood furniture instead of semi disposable MDF crap. Metal over plastic. Long term sustainability over short term savings.

mos_8502, to random

Round two: How about this for generating the main CPU clock?

The CPU initially uses the 32KHz TOD clock (that's just how the chip is designed), and can switch to the "fast clock" (FCLK) input under software control -- so we will use the I2C bus to program the FCLK speed in this Si5351A. The default ROM can set it to 8MHz, and maybe there can be some API for configuring it dynamically. The CPU should work anywhere from 12MHz up to 20MHz, but it's only rated for 8MHz because WDC.

mos_8502, to random

Them: "Isn't using programmable logic in a retro design cheating?"

Me: "Go and ask the engineers of the ZX Spectrum and Commodore 64, both of which used the 1980s equivalent of CPLDs to implement glue logic."

mos_8502, to random

CUPL is a terrible HDL, but it's what the cheap 22LV10C uses.

If someone has a toolchain I can use to turn Verilog into something I can burn into a 22LV10C with a Minipro type ROM programmer, I would love to know.

mos_8502, to random

They want $30 for this. I would find it fun to turn it into a DIY retro computer CRT. But not for $30. At $10 I would consider it.

Perhaps something like a Superfo Harlequin 128K in a PET like enclosure? With a mechanical keyboard?

mos_8502, to random

I wish everyone on Facebook who is screeching and wailing because She-Hulk might get a second season a very death by autoerotic asphyxiation in the closet of a preschool.

mos_8502, to random

If you know a better way to test this thing at various clock speeds cheaply, I'd like to hear it.

mos_8502, to random

Should exist: Fediverse client with Usenet client style UI.

mos_8502, to random

Huh. Well that's never happened before…

mos_8502, to random

“If you block Threads you don’t care about an open web” has big “blocking me is censorship” energy.

mos_8502, to random

I absolutely believe, based on knowledge of the subject matter, that real, sentient, artificial intelligence is not only possible, but will eventually be created.

I also do not believe for a second that current technology is anywhere close to the level needed to do the job, and even if it were, our understanding of cognition is far too low to actually pull it off except by accident.

mos_8502, to random

I'm not throwing my skirt over my head and running around with my bollocks aflame about it, but given the utter failure of moderation they show, I'm perfectly fine with anyone domain blocking or defederating Threads who wants to, even without the corpo bullshittery.

I tend to judge the company people keep. Willing association with transphobes, homophobes, antisemites, and other such types I will judge most harshly.

mos_8502, to random
mos_8502, to random
mos_8502, to random

Meta trying to take over the Fediverse reeks of Google trying to moderate the alt.* hierarchy in Usenet. It’s just not practical. I can see why they’d try, but the attempt is doomed.

mos_8502, to random

Muss die blinkenden Lichter haben.

mos_8502, to random

Oh, you're into electronics? Calculate the resistance of this part, then.

mos_8502, to random

When I spend my "fun" budget in January, that's going to include the NEC V20 and Proton PT8010AF chips needed for the Micro8088, but I should probably also order some PCBs for other stuff for that. I know I definitely want a PicoGUS in there, but I'll be needing a floppy controller, an IDE controller, serial and parallel controller, and some kind of video card. I don't have a CGA, EGA, or MDA compatible display, so maybe something like the Graphics Gremlin is appropriate?

mos_8502, to random

The GitHub repo for Sentinel 65X is now public, for your viewing pleasure.

The design would not be in anywhere near the shape it's in were it not for the assistance of @swetland and @RenewedRebecca. It is my sincere hope that this leads to an actual product release, and from there to an actual user community.

PDF of the current schematic: https://github.com/studio8502/Sentinel-65X/blob/main/kicad/Sentinel%2065%20V2/Sentinel%2065%20V2.pdf

Repo:
https://github.com/studio8502/Sentinel-65X

mos_8502, to random

My gods, a far-too-high percentage of Star Trek fans are pathetic.

"The original Enterprise didn't have a kitchen!"

"But how will they explain the visual downgrade!"

"CANON VIOLATION!"

"TREK IS RUINED"

Fuck you, and fuck your mother for failing to swallow, fanboy. It's a drama, not a documentary. Shit changes. Stories change in the telling. Learn to fucking cope, or go rewatch your old VHS tapes of TOS.

mos_8502, to random
mos_8502, to random

Motherfucker… are you on crack with that price? Even in Australian dollars that's fucked.

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