John Kortink

Musings about hobby hardware/software development (among few other things)

[John Kortink @WindfallNL]

@thePickleizer Ah yes. Go 'up' while pressing 'J' to meet some special folks.

[John Kortink @WindfallNL]

This is what happened when I shoehorned a 6502 Second Processor into GoSDC ULT and ran both 6502s at 70 MHz (only I/O and VRAM at 1 or 2 MHz) : https://t.co/jwciaiwby0. It's the ultimate kind of unplayable.🤪

[John Kortink @WindfallNL]

@thePickleizer Ah yes ...🙄We were kids. Just kids. We didn't know any better ...🤔But we tried.

[John Kortink @WindfallNL]

Acorn Electron said 'I can do that too !'. And so it did. A humble Elk running at 80 MHz (processor/main RAM), doing 'a bit of BASIC' ... Heh🤓

[John Kortink @WindfallNL]

On an Acorn BBC running at 80 MHz, GoSDC can read files at roughly 800 KB/sec.🤪If I add a special 'port to RAM' instruction to my 6502 core, this might increase, but I have reasons to believe that the SD card has become the bottleneck here (at least in SPI mode).

[John Kortink @WindfallNL]

@thePickleizer Wouldn't it be great if, only that day, PCB manufacturers offered orange as a colour.

[John Kortink @WindfallNL]

Acorn BBC model B running at 80 MHz, slowing down to 1 or 2 MHz for I/O and framebuffer writes.🤓Who needs a second processor to accelerate their Beeb. Gotta check out some games, and see what happens.

[John Kortink @WindfallNL]

@thePickleizer You think dutch people want everything to be orange, don't you, Richard.🙄

[John Kortink @WindfallNL]

@thePickleizer It didn't want to, but I said 'Look, the board is blue ! Blue !'. And then it finally said 'Alright ...'. PFM.

[John Kortink @WindfallNL]

Making a one-off GoSDC ULT (BBC model B only). Same arrangement as GoSDC-Atom ULT : processor and RAM running at 80 MHz or so, and all I/O at 1 or 2 MHz (whatever the BBC's clock stretch circuitry does).

[John Kortink @WindfallNL]

Who knew it would ever be made, The New Avengers in 4K, but it's a spectacular upgrade, compared to the shoddy DVDs that were the only thing around for 20 odd years.

[John Kortink @WindfallNL]

Acorn Atom running at 80 MHz, slowing down to 1 MHz for I/O (8255/6522 and video RAM).🤓For a video see https://t.co/trY02d0jtV (there's a second one too).

[John Kortink @WindfallNL]

GoSDC-Atom ULT is toddling around. With equal clocks for 6502/RAM and the motherboard, the Acorn Atom it's in can run at 7.69 MHz (14 MHz really, since my 6502 core is roughly twice the speed of a real 6502). With separate clocks, 80 MHz should be possible😀(160 MHz benchmark).

[John Kortink @WindfallNL]

Building an Acorn Atom (actually two), based on a reverse-engineered PCB (thanks, mister DragonPlus). First one boots (yay). No keyboard yet. I have the 'issue 5' keyswitches but I first need to think about a keyboard plate.

[John Kortink @WindfallNL]

Making a one-off variant of GoSDC-Atom PRO that will allow me to run my own 6502 core, at ludicrous speeds (throttling back to 1 MHz for everything still on the motherboard). The resources of the 10M50 should allow a 6502 second processor to be tacked on as well.

[John Kortink @WindfallNL]

Built a Tauntek LogICTester, which improves logic testing by providing analog details.

[John Kortink @WindfallNL]

Changed all the TTL chips of an Acorn Atom to ceramic versions, and used the opportunity to get faster ones wherever it could help with overclocking. 5 MHz still fails, but 4 MHz seems rock solid (although I won't be doing any empirical research to prove that).

[John Kortink @WindfallNL]

Updated the Linux version of 65Link, so an Acorn Atom can now use a PC running Linux as a file server. Might even work from a VM (if passthrough of PCI-E I/O is supported).

[John Kortink @WindfallNL]

Did a quick port of the Acorn Atom Software Archive to LFS (65Link). A few minor menu changes, then store the files in 1115 volumes.🧐

[John Kortink @WindfallNL]

If you had a basic Acorn Atom, and all you wanted for Christmas was 65Link (which is damned unlikely, but bear with me), then besides having to wait for another six months, it could take this shape.