Random hardware ideas!

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Cristian
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Re: Random hardware ideas!

Postby Cristian » Wed Apr 26, 2017 9:27 pm

Dave wrote:Christian, no! Just no! Obviously that QL has crashed, because all the microdrives are on at once!

:lol:

Dave wrote:I think 2 extra is a reasonable limit. Don't you?

Actually, for me is not so crucial to add more MDVs. Two is the right number... if only they were reliable and robust devices!


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Re: Random hardware ideas!

Postby Dave » Wed Apr 26, 2017 10:03 pm

Well. Hmmm.

With what I have been graciously handed by Nasta, Peter Graf and Silvester, currently we have the following complementary options that fit well together:

Ethernet:-
CP2200-based. 10Mb/sec full duplex. Non-existent driver would be loaded in RAM.

QL-SD:-
2x SD card slots, driver in ROM. Could use the new driver by Alain Haoui?

USB:-
2x USB host ports. Only Human Interface Devices (HID) like specific keyboards and mice might be 'easy' and not much else is ever likely to work without significant effort by individuals. This is only of interest because the cost to add it is low, but the potential benefits are quite big - especially if a QL-type board might find embedded uses in the future.

1MB SRAM:-
Full speed, 768k or 896k max available, shadowing.

Less likely options, due to lack of complete schematics/details include battery backed clock, sound device and PS2 port. If this information magically appears, that might change.

Individually, all of these things are quite easy to do, but combined it might be a bit more tricky. I'll play with the low hanging fruit first - those things which have been done and shown to work. QL-SD and 1MB RAM. Then I'll work on ethernet and finally USB.

PLAYTIME!


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Peter
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Re: Random hardware ideas!

Postby Peter » Thu Apr 27, 2017 9:47 am

Will (Flash) EPROM be there?

As for the 'non-existent' ethernet driver, and 'easy' USB HID driver:
The former has at least an existing, tested hardware to be developed on.

Not sure about the 'big' potential benefit of USB mouse and keyboard. For a keyboard or 3 button mouse with scrollwheel: What do I gain over PS/2 (or PS/2+USB combo)?


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dilwyn
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Re: Random hardware ideas!

Postby dilwyn » Thu Apr 27, 2017 12:12 pm

Cristian wrote:
tcat wrote:Hi,

3D printed QL-matching case


https://www.dropbox.com/s/0le6rd2a3mnm8ur/QL_8.jpg?dl=0

He he, I like it.


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Peter
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Re: Random hardware ideas!

Postby Peter » Thu Apr 27, 2017 12:54 pm

Maybe the lefthand side of the case should be similarly long to provide room for some extensions cards. :P
I still remember seeing QLs with a half meter of hardware on the left...


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Re: Random hardware ideas!

Postby Dave » Thu Apr 27, 2017 5:57 pm

A backplane like mPlane, but doubling over in front of the QL. This would make a handy armrest. In the middle of winter you could also warm your fingertips on the forest of little heatsinks.


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Re: Random hardware ideas!

Postby Dave » Thu Apr 27, 2017 6:02 pm

Peter wrote:Will (Flash) EPROM be there?


No. I'll have to save working on that for the Super Duper Gold Card*

Peter wrote:As for the 'non-existent' ethernet driver, and 'easy' USB HID driver:
The former has at least an existing, tested hardware to be developed on.


It's a chicken and egg situation. If it is available and someone wants to use it for a specific device, to support a special keyboard or disability aid, etc., at least a new option is there to support a modern standard device. USB is HARD because companies are incredibly secretive about their drivers and device inner workings. Luckily, FTDI has host and device ICs so we can also put our own USB device IC in things too.

Peter wrote:Not sure about the 'big' potential benefit of USB mouse and keyboard. For a keyboard or 3 button mouse with scrollwheel: What do I gain over PS/2 (or PS/2+USB combo)?


Nothing except the choice.

* I'm jokingly referring the the 68020 card as the "Super Duper Gold Card" but that is not its name. It does not exist yet. There is a lot of work to do.


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tofro
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Re: Random hardware ideas!

Postby tofro » Thu Apr 27, 2017 7:18 pm

SSS should be reasonably simple in case you have sufficient CPLD capacity and pins. It consists of an 8-bit port, an R2R ladder, a timer and an interrupt, maybe an OpAmp or a transistor in the simplest case. Adding a hardware queue like in Q68 might be a bit more demanding.

In case you use proper addresses, even the driver could be re-used.

Tobias


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Peter
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Re: Random hardware ideas!

Postby Peter » Thu Apr 27, 2017 7:35 pm

Dave wrote:
Peter wrote:Will (Flash) EPROM be there?

No. I'll have to save working on that for the Super Duper Gold Card*

But that would make the card dependant on loading the SDHC drivers from microdrive!
Or dependant on a second extension card for mass storage with feed-through QL bus.

I would at least add a cheap little PLCC32 64KB OTP EPROM. Otherwise this could become a disaster.

Such a little EPROM, however, could make large Flash redundant, if you add the option to switch its area to RAM. It could contain a loader and read the OS from SDHC. And if writing a loader gets too hard, it could at least contain the SDHC driver.


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Peter
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Re: Random hardware ideas!

Postby Peter » Thu Apr 27, 2017 8:13 pm

tofro wrote:SSS should be reasonably simple in case you have sufficient CPLD capacity and pins. It consists of an 8-bit port, an R2R ladder, a timer and an interrupt, maybe an OpAmp or a transistor in the simplest case.


The reason why it was so easy on Q40/Q60 came from the fast CPU speed, which
(A) allowed feeding the DAC registers with little time jitter
(B) did not slow down the whole system by the interrupt overhead

In this case, there would usually be only a 68008. So to achieve (A) you would at least need a second register level, not only the output register. For stereo, this means 2x2x8=32 Flipflops, which might already be 20...50% of all you got on an affordable 5V tolerant PLD. Those chips have relatively large combinatorial resources, but few flipflops.

(B) Looks almost impossible. Although a Q60 is over 100x faster than a QL, I vaguely remember the 20 kHz sound interrupt costs more than 1% CPU time. The 68008 would have little to no CPU time left. And the SSS data must come from somewhere...

The only solution I can see would be a hardware FIFO. Not necessarily as large as Q68.



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