Monday, September 21


Daily News Stuff 21 September 2020

The Clocks Were Striking Thirteen Edition

Tech News

  • The new version of Chrome has fucked up the comments.  I'll try to fix that tomorrow.  I can at least work around it.

  • China is at war with everyone.  (ABC)

    Including, of course, the Chinese people themselves.

    This is the Australian ABC reporting the story, not the US ABC, proving that a bunch of godless Lenin-worshippers suckling on the public teat for sixty years are more honest than the American mainstream media.

  • The US Air Force has designed, built, and flown a new fighter jet prototype.  (Defense News)

    In under a year.

  • I've done the instruction code layout for the Mirage M1100 CPU - the 11-bit variant.  It was instructive; for example there is now only one type of address postbyte, because one extra bit was enough to combine the indexed and extended register addressing modes.  For regular opcodes the extra bit defines the operand size - byte or word - and thus switches between 11-bit registers A, B, C, and D, and 22-bit W, X, Y, and Z.

    That freed up enough code pages that I could add in instructions to add or subtract 11-bit values to 22-bit registers, with and without carry.

    It also tells me that the best version of this will be the 13-bit one.  Originally that was going to be a weird dual-issue stack-based system, like an Analog Devices SHARC on crack.

    I might still do that version, but it would require an entirely new compiler and would generally be a pain in the bum.  The sane version will come first, but I'll need a new name for it.  (Pokes  The Vision, that's just the ticket.

  • Rule 1 briefly suspended.  (Ars Technica)

    Rule 1 is of course never read the comments but that doesn't apply on personal blogs (mostly) or on Ars Technica's Rocket Report posts.

    Still on display though is the usual Ars Technica trait of aggressively downvoting anything you disagree with; the only difference here is that the point of disagreement isn't politics.

    Also, of course South Australia has a town with the most offensive name possible.

  • From watching gameplay videos on YouTube, I have a whole bunch of minimum specs for these systems, most of which I fortunately already had in mind.

    • 32 colours selectable from 512.  16 colours just doesn't quite do it.  64 is better.  More than 64 starts to make it too easy, and the results look noticeably different.

    • 480x270 resolution.  Yes, this is mostly to upscale nicely to a 1080p monitor, but also because 320x200 isn't actually very good and looks like crap on a large screen.

    • 4-voice music and 2-voice sound effects.  Can be stereo, mono, or split channels like the Amiga.  Music can be wavetable or PCM, or PSG or FM synthesis if the number of voices is increased (two PSG voices can produce one FM voice, for a start).  The Sharp X68000 which we heard in action with Dragon Spirit had 8-channel FM synthesis and sounded pretty good.

    • Some way to do parallax scrolling.  Dual playfields, a really fast blitter, a ton of sprites, tile rotation, something.

    • Hardware smooth scrolling in both X and Y.  Scrolling by a character at a time on an arcade-style game looks like poo.

    • Multi-colour sprites.  Four, or better, eight colours per sprite.  And at least eight of them.

    • So basically an Amiga.  Huh.

  • So in this parallel and much nicer reality, these systems came out one after another starting in 1983 with the 10-bit Imagine, followed in 1984 by the 11-bit Mirage, the 12-bit business-oriented Dream in 1985, then the 13-bit Vision and the 9-bit Phantom in 1986.

    Before 1983 you couldn't meet the specs above at a sane price; by the mid-90s systems were way more complex than anything I want to emulate.  The SNES came out in 1990 and already the video chip in that is Nyarlathotep in silicon form.

    My window of interest essentially starts in 1983 with the Fujitsu FM-7 and ends in 1992 with the Sharp X68000 Compact, the last model with an original-generation 68000.  But that's plenty of room to play around in.

Twelve Hours Worth of Chiptunes Music Video of the Day

Via the X68000's Yamaha OPM 8-channel FM synthesizer.  Don't say I never take you anywhere.

Disclaimer: Ah, there's the music from Eco.  Wait, stop changing scenes and making it change music tracks, go back to-  Ah, thanks.  Wait, you did it again, stop that!

Posted by: Pixy Misa at 11:17 PM | Comments (5) | Add Comment | Trackbacks (Suck)
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1 "Before 1983 you couldn't meet the specs above at a sane price."  And nowadays you can get 120MHz ARM cpus for under $5.  Amazing.

Posted by: Rick C at Tuesday, September 22 2020 01:22 AM (eqaFC)

2 That reminds me - I found a page charting memory prices per megabyte from 1957 through to today.  I'll post it in tomorrow's news stuff.

Posted by: Pixy Misa at Tuesday, September 22 2020 01:46 AM (PiXy!)

3 I know you did some of this research a while ago, but I've been poking around Microchip's website--long-term, I want to design my own keyboard PCB, and I am thinking I want to replace the Arduinos usually used with something beefier, because they have such constrained memory (2.5KB SRAM, 30K flash, for example, which really limits the kind of stuff you can do.  On my Kyria, adding a simple animation ( eats up enough space that you lose the ability to use some of the other functionality, like the serial monitor.  I'm trying to decide for now if a 64-pin QFP is enough or if I want to mess around with larger sizes or, G-d help me, messing around with 100 or 144-land BGA (which will probably mean 4-layer PCBs) because when you move to the $5 ARMs you first off get a lot more flash/ram, but also you get the ability to use serial flash, not just for storage, but you can run code via execute-in-place.  (Turns out there are even XIP SRAMs, but they don't work with AVRs, you gotta step up to ARM.)
Microchip sells 300MHz Cortex-M7 CPUs with a meg of flash and 256K (iirc) of SRAM for like $13 in single quantity.

Posted by: Rick C at Tuesday, September 22 2020 02:43 AM (eqaFC)

4 I was looking at the STM32H750, which has 128k of flash and 1M of RAM, because it's easier to add flash to a board than external RAM.  480MHz, 100 pin LQFP, about $7 in qty 1.

The STM32F730 is a similar part but lower-spec: 64k flash, 276k RAM, 216MHz, 64 pin LQFP, $4.50 qty 1.

For a one-off though getting the right part far outweighs a few bucks in cost.

Posted by: Pixy Misa at Thursday, September 24 2020 12:29 AM (PiXy!)

5 It turns out you can even get serial SRAM, if your micro supports XIP! is an 8MB psuedo SRAM that operates via QPI for $1.75, bare 8-pin DIP, qty 1.  I don't have any but they seem to work more or less just like serial flash.

I ordered some Atmel Cortex-M4s (ATSAMD51J18A) to play with that just arrived today. TQFP-64, which I'm a bit apprehensive about, but I've got some breakout boards on order and have been watching Youtube videos about, 120 MHz, 256K flash, 128K SRAM, already being used in custom keyboards and supported in a couple of RTOSes. $3.70 qty 1, IIRC, and I got 4 in case of oopsies.

Posted by: Rick C at Thursday, September 24 2020 06:25 AM (eqaFC)

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Apple pies are delicious. But never mind apple pies. What colour is a green orange?

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