Day 323 - #retrorandom - Spotted at Made In Japan at @computinghistory.org.uk back in 2023. It's a Gakken Compact Vision TV Boy - the only games console that I'm aware of based on the MC6847 graphics chip, which we all know and love in the Dragon, Coco and Tandy MC-10!

Guess what machine uses the alternate register set for interrupts without saving them….temporarily bodged by using the 8080 runtime until I setup im2.

Screenshot from bringing it up yesterday, for once I didn’t use the ZX font!

「List of home computers by video hardware」には、1978〜1985年に登場した家電級PCが載っているよ。MC6847チップ搭載のモデルは背景とテキストだけだったけど、後期ではスプライトやハードウェアアクセラレーションを追加し、色彩豊かな画面を実現したんだ。🎮🖥️ en.wikipedia.org #トリビア

「List of home computers by video hardware」ってリスト、実は昔の家庭用パソコンの画面表示についてまとめたものなんだよ！ 👾

MC6847っていうチップが使われていて、初期のゲーム機やパソコンの色や解像度を決めたり、キャラクターを表示したりしていたんだって。 acorn Atom や APF Imagination Machine 、 TRS-80 MC-10など、懐かしい名前もたくさん載っているんだよ。👀✨ 昔の技術に触れると、今のデジタル社会への道のりが分かるような気がするよね！... en.wikipedia.org #トリビア

Temporarily back on the Laser200 now that I’ve got the milliamp-tester going. ROM side is all good. Display side however is HAUNTED.
Pictured is the display chip, VRAM and the LS245 buffer that controls access to the video side. The red line is the path of D0 according to the schematics. /2

Trying to create a common codebase for mc6847 targets within z88dk. Currently at the mashing together stage and marvelling at the lack of commonality when handling text mode.

#CMPMicroMay Day 22

Here be Dragons, Dragon 32 to be precise, two of them which i think makes them one Dragon 64 ? thats how it works right ?

Built in Swansea Wales, this micro is a Motorola 6899E cpu based computer with the MC6847 Video Chip.

Cousin to the TRS80 CoCo

That monitor needs a little TLC. It's all wobbles :-)

I see the Atom uses the MC6847 (like the TRS-80 Color Computer, Dragon 32 and many others.) Wikipedia says initial versions only output NTSC color or at least 60hz video without color, funny!

And even 2K of RAM is twice as much as the ZX80/81!

Some of the tracks will be under the chips. Thankfully some kind soul has recreated the Dragon 32 Issue 2 PCB in Kicad. Using that I can quickly isolate tracks and work out what is going where. I think, if memory serves, the clock signal is missing from Pin 33 of the MC6847, which doesn't help.

thanks to @flohofwoe.bsky.social's terrific MC6847 VDG implementation, i was able to add full resolution graphics support to my APF-MP1000 emulator with relative ease.

the internal char/color set of the VDG matched the real MP1000 palette quite closely, too.

a screenshot from APF Rocket Patrol:

How did you get those Sanyo PHCs... Based on #6847. Those are hard to buy. #mc6847 #motorola

Yeah, that's due to the MC6847. On PAL machines it's limited because NTSC colour tricks aren't possible. In high-res mode, the graphics are B&W but look as good as that of Spectrum games.

There's joystick adapters now and new stuff that shows what the Dragon can do beyond the green, green grass. 😀

I didn't know anybody who owned a Dragon and whilst I saw the software in shops, not once did I see the machines. The only promotion that I recall seeing was the Weetabix one (h/t: @nostalgianerd.com re the photo)

It's a decent computer let down by the MC6847 VDG, which was old hat even by 1982.

The clock signal is not right to the MC6847. It comes out of Pin 11 of IC23, nice steady 3.55ish MHz signal. That's fed to Pin 6 of IC14, still a nice steady 3.55ish MHz signal.

And the same MC6847 chip which was in my first computer: VZ200 😀