Sunday, July 21


Daily News Stuff 21 July 2019

We've Got It All Edition

Tech News

  • Only two things are certain: The death of Stadia, and taxes.  (One Angry Gamer)

    And we're trying to do something about taxes.

  • NASA's Orion crew capsule is officially complete.  (Tech Crunch)

    A test flight to lunar orbit is planned for next year, using the SLS.

  • SpaceX's Starship is expected to have a test launch within 3 months.  (Tech Crunch)

    Their StarHopper had an engine test a few days ago that ended abruptly due to anomalous fuel conditions.

    The Hopper seemed to be fine afterwards, at least outwardly.  Looked spectacular though.

  • HDMI is a pain in the bum.

    If you want to output a VGA signal, you can do that with a few TTL chips and a handful of resistors:

    Or a PIC driving an SPI serial bus and a handful of resistors:

    Or an ESP32 with some internal timers and a handful of resistors:

    But if you want to do HDMI, well, first you have to pay $5000 to the HDMI Licensing Association.  Second, whatever pixel clock you are using, the HDMI clock is ten times as fast.  You can just barely get that out of a low-end FPGA like the Lattice iCE40, using DDR signals, if your pixel clock is no more than 25MHz. 

    (And I'm not sure whether pixel-doubling tricks work with HDMI, so that limits you to 640x480 as the one and only available resolution.)

    You can buy DVI interface chips, which have exactly the same video signalling as HDMI at up to 1080p (you can get a DVI<->HDMI cable for $6 and it will work perfectly as long as you don't go above that resolution).  There's no license fee, no NDA, and no royalties.  It's still basically impossible to generate the signal yourself, though.

    You could use a Texas Instruments TFP410, but if you're working with parts like that Amiga-on-a-chip (the STMicro H750) it would be the most expensive component in your entire build.  480MHz Arm microcontroller with 1MB RAM and onboard blitter and LCD controller, $10.91; DVI transmitter $11.24. 

    (A$, qty 1.  Volume prices in US$ will be far lower, but I need to buy one of them to start with.)

    The NXP TDA19988 is described as an HDMI transmitter but would be equally happy being wired to a DVI socket, and at $7.94 would at least be only the second most expensive component.  For comparison, a DisplayPort to VGA adaptor, which is actually complicated, costs $3.00, and a three-port HDMI switch costs $2.40.

    It's at least an option, probably.  And it's cheaper than a proper video DAC that will run at 1080p60 resolutions - the cheapest one I've found is $9.80.  I wasn't planning to use one of those, though;  15 bit colour can be done well enough with cheap 0.5% resistors.

  • Speaking of Amigas-on-chips, I found another one.  This is the Renesas RZ/A1L.

    Performance is very similar to the STMicro H750 - it's a 400MHz Cortex A9 vs a 480MHz Cortex M7, and the A9 is 20% faster than the M7.

    It has a blitter and a video controller, and all the usual periphery like counters, timers, DMA, PWM, Ethernet, USB, SPI, SPDIF, and SD/MMC.

    The big difference is that this is a microprocessor rather than a microcontroller, meaning that (a) it has no on-board flash at all, so it has to have an external boot ROM to do anything, and (b) it has 3MB of RAM vs. 1MB on the H750.

    Oh, and it seems to have four independent playfields - four graphics layers - compared to two on the H750.  So you could have a static game background, a background sprite layer, a static foreground, and a foreground sprite layer, with all the hard parts done by the hardware.

    Which makes it more like the Amiga 1200 than the Amiga 1000. 

    It also has several siblings - the A1LC with 2MB RAM, the A1M with 5MB, the A1H with 10MB, and the faster A2M with 4MB and hardware sprites.  (But only 16 of them; I checked.)  They're not all pin-compatible, though the A1M and A1H are.  And they're available in QFP, unlike many higher-end chips which are only in BGA and a pain for small production runs.

    The A1M, A2M, and A1H also drive two displays simultaneously.  Not sure if they can drive two displays with four graphics layers though.  And it looks like the display controller can do the pixel-doubling and line-doubling that I need without having to constantly fiddle with control registers.

    The RZ/A1LU starts at A$23.52 qty 1.  That's twice as much as the H750, but that chip is an anomaly; the STMicro F469, which has 384K of RAM and runs at 180MHz (but does have 2MB of flash) costs $23.46.

    The 5MB part is nearly double the price, though.  Avnet supposedly have it cheaper, but their search function is bugged all to hell right now.  But hey, a dual-display 400MHz Amiga-on-a-chip for about US$28 is not exactly bad.  (Price does not include two of those darn DVI transmitters.)

  • You also need a license for SD cards, it turns out.  If you want to build something that SD cards can plug into, you need to pay $2500 a year.  Good old MMC, no license fees.

    Wonder why all those cheap Chinese gadgets have TF cards - "TransFlash" that look and work just like micro SD but technically aren't?  There you go.

Video of the Day

It was thirty years ago today.  Approximately.

Disclaimer: Please do not adjust your set.

Posted by: Pixy Misa at 11:23 PM | Comments (2) | Add Comment | Trackbacks (Suck)
Post contains 924 words, total size 7 kb.

1 "What do saves and metadata matter if the service is dead? You won’t have anything in this scenario. "
LOL--the RIAA would be glad to tell you:  "buy it again, dummy."

Posted by: Rick C at Monday, July 22 2019 02:02 AM (Iwkd4)

2 Or if you live in Australia, "Buy it again, dummy.  This item is not available in your region."

Posted by: Pixy Misa at Monday, July 22 2019 02:28 AM (PiXy!)

Hide Comments | Add Comment

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

55kb generated in CPU 0.6728, elapsed 0.5703 seconds.
58 queries taking 0.5353 seconds, 343 records returned.
Powered by Minx 1.1.6c-pink.