Single-chip microcomputer?
rokicki
Posts: 1,000
Some friends and I have been bemoaning the lack of inexpensive accessible programmable computers for the kids, much like the microcomputers of the early 80's. Anyone remember the Color Computer? Commodore 64? Things like that.
The Propeller looks like the first single-chip (or near-single-chip) solution capable of replacing those. I'm thinking a small box with nothing but a NTSC video/sound out, standard PC keyboard (PS/2) in, and wallwart power in. The Propeller plus an EEPROM (plus maybe a serial SRAM), along with a few resistors and a supply regulator should do everything we need.
I'm thinking a simple built-in basic interpreter just like the old boxes. EEPROM will provide the program storage. No internet, no crazy graphics, no exorbitant memory---just a simple box people can learn to do simple BASIC programs on. Heck, with an EEPROM we can even make it come preloaded with 101 cool starter programs.
Is this totally insane? I remember all the fun we had with the old Apple IIs and the like, and am sad that kids today don't get the same thing.
I showed my ten-year-old nephew a TRS-80 color computer the other day, and he took to it right away---even though he's a total video game head. And he had a blast writing (right away!) little programs that counted, that printed different things. I am sure he's not the only kid like that.
The Propeller looks like the first single-chip (or near-single-chip) solution capable of replacing those. I'm thinking a small box with nothing but a NTSC video/sound out, standard PC keyboard (PS/2) in, and wallwart power in. The Propeller plus an EEPROM (plus maybe a serial SRAM), along with a few resistors and a supply regulator should do everything we need.
I'm thinking a simple built-in basic interpreter just like the old boxes. EEPROM will provide the program storage. No internet, no crazy graphics, no exorbitant memory---just a simple box people can learn to do simple BASIC programs on. Heck, with an EEPROM we can even make it come preloaded with 101 cool starter programs.
Is this totally insane? I remember all the fun we had with the old Apple IIs and the like, and am sad that kids today don't get the same thing.
I showed my ten-year-old nephew a TRS-80 color computer the other day, and he took to it right away---even though he's a total video game head. And he had a blast writing (right away!) little programs that counted, that printed different things. I am sure he's not the only kid like that.
Comments
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
Actually, you hit on the exact reason behind Chip Gracey's reason for designing it. He was one of those 'kids' of the late 70/early 80's who did all kinds of cool things that PC's just don't let you today. He wanted a chip with a great cool factor to excite young minds like his was. I was also one who use to program 6402 ASM on my Commodore PET to make all kinds of programs, and it really gave me a great background in understanding systems. Things I would know where to start on today's PC.
-Martin
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Martin Hebel
Disclaimer: ANY Propeller statements made by me are subject to my inaccurate understanding of my limited time with it!
Southern Illinois University Carbondale -Electronic Systems Technologies
Personal Links with plenty of BASIC Stamp info
and SelmaWare Solutions - StampPlot - Graphical Data Acquisition and Control
Post Edited (Martin Hebel) : 2/26/2006 5:08:16 AM GMT
http://forums.parallax.com/showthread.php?p=464494
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Chris Savage
Parallax Tech Support
csavage@parallax.com
when we were kids. I'm not sure about the Commodore, but the Atari only had a 1MHz system clock and was impressive in it's own right!!
Comparing dinosaurs to modern man, the Propeller is a highly advanced and very capable machine.
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
I had a Color Computer and this really wasn't that bad. You save a program or a bit of data rather than alway starting over.
It also taught a lot of principles of electro-magnetic storage media in a very simple format.
I seem to see a lot of people don't understand how complex a floppy or hard disk really is and how much manipulation is required to go from a simple stream of data and get it onto a spinning disk.
So, I guess what I am asking is can the Propeller also provide an audio modulated output to record and then decypher a playback as digital data.
This may all seem to be redudant when you consider programing it via a PC. But, if you want to give the kids a completely autonomous, programible device, you may have to provide it's own 'mass storage'.
Limitations can be a good thing.
Kids learn to economize and think of alternatives. I think I heard that Lee Travino learned to play golf by hitting an aluminum foil ball with a stick as he was too poor to get either a golf club or the ball, but he was a caddy on a golf course. Still, it demanded tremendous control to do so accurately and to get any distance at all. {It certainly worked for him.}
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
I have a CoCo-3 or two around here somewhere(grin) I go back to Jan 81 when I got my CoCo..
Believe it or not it is still around,I am the Manager of the coco/Os9 forum on what was Delphi(Delphiforums) as it is known now, the winXP1 and the Experimenter forum as well,this is very interesting!
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Enjoy
Dennis McMillan
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The Pioneering spirit...
There's something about being the first to do something on a new piece of HW. There's also the possibility of Hacking in its purest sense, making the HW do something that the manufacturer never thought it could do.
Lets face it, the PC platform is just about dead when it comes to real creativity, anything can be done if you just throw enough RAM and CPU power at it, and generally that is how it is done, too...
But back in the 80s, people took a computer, no matter how limited, and made them WORK, despite the limitations.
There's something just... satisfying about that...
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Don't visit my new website...
Oliver
It is about the mental exercize and watching the world go by.
Oliver, I can hear you about interupts.
I am trying to do something that requiers using several threads in an SX with the ISR and I still have trouble envisioning it. There really isn't a 'tutorial' about this, just high end users literature. Slowly the light is coming on, ever so slowly.
Yeah, I was in San Francisco when all this was happening, but really didn't have the time to keep up with it [noparse][[/noparse]I had to work building office buildings as a Union Carpenter for my day job].
In my slow time [noparse][[/noparse]during layoffs] I would try to catch up and went to HAM Swap meets at Foothill College [noparse][[/noparse]in the heart of Silicon Valley]. That was probably the world's greatest electronics flea market [noparse][[/noparse]or at least one of them]. Everything that was being put in dumpsters in Silicon Valley seemed to be arriving there. Also, whatever engineers wanted to get out of their garages passed through. Tubes, Scopes, Chips, old audio, very old radio, NASA junk, old documentation, early Ampex, early TV .... Just talking to people was an education.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Post Edited (Kramer) : 2/26/2006 4:19:31 PM GMT
Right; I was hoping we could get a big enough EEPROM or serial FLASH where they could use built-in "storage" for their programs.
This doesn't solve the "swap programs with friends" problem though. One solution to this is to use cheap SD cards, but now we're talking an SD socket which is another cost item.
The hardest part of all this will be (as always?) the software. I'm anxiously awaiting the release to see what "comes with" the chip.
SD cards seem to be jumping into my hands. I bought 2 or 3, but now I have 5 or 6. THE SD CARDS seem to require a File Allocation Table and DOS file format. This requires buffering, conversion, and management. [noparse][[/noparse]more costs]
On the other hand. FRAM memory chips seem to be ideal with an SPI interface.
Audio data storage is more of an engineering artifact [noparse][[/noparse]as it really takes up more space if you use digtal audio]. And, cassette recorders are all but gone.
Educationally it still gives a very clear idea of how modulation plays a key role in moving between digital and audio and radio.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
It shouldn't be too much of a problem finding a plug they can be mounted onto to make it easy to swap them in and out of a system.
The biggest problem is really to create a decent Filing system for them.
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FRAM looks cool and all, but seems to be too cutting edge; I'd hate to write a ton of software dependent on FRAM and have it go away.
The main issue with the EEPROMs appear to be the size; 32KB total (24c256) doesn't leave much room for the kid's programs and the system software. I think the system software will probably be around 32K by itself (the propeller for all of its magnificent features will probably not be the king of code density). I'd like to let the kids have at least 64K worth of program storage and preferably much more than that; truthfully I think a total of about 1MB nonvolatile storage will be a sweet spot.
The downside is we are talking three external memory devices already: EEPROM boot, flash for nonvolatile, and SRAM for working RAM. I suppose that's why the FRAM solution is attractive. I'll have to study the chips.
The right thing to do may be a 24c256 to boot with and an SD slot for nonvolatile. Are there any inexpensive, widespread larger serial EEPROMs than the 24c256 in widespread use?
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Jon Williams
Applications Engineer, Parallax
(I'm assuming that the user isn't supposed to write the programs on a PC, then transfer them on a MMC or EEPROM)
Or, how much space would a simple editor take if you split it up?
I can't remember any machine spending much less than 16KB on these things.
Yes, I know that if it's written in Spin we have 32KB to work with, but do we really want to interpret one language with another (semi-)interpreted language?
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I think the Sharp 730 was actually based on the Z 80.
Don Myers
And the ZX80 (integer only) only had a 4K ROM.
I won't say it's impossible.
Bean.
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That's definitely a concern, which is one reason I want to get the development board and find out what we can do with what is
built-in. The code density of the old microcomputers was pretty high (especially for the Z80 and 6809), and I'm shooting for
something essentially equivalent to Coco Extended Basic plus load/save by name to some filesystem, so we're probably looking
at the equivalent of 6809-level 20K or so. Ideally a lot of what we need is already in the 32K ROM SPIN interpreter, if we can
figure how to reuse what's there. And since I visualize all user program and data residing in external RAM, we may be okay.
The tricky part may well be the 512-instruction-limit in the cogs; I'd hate to think we'll spend most of our time shuffling
instructions into and out of the cog memories. I'm especially concerned with how many instructions a reasonable FP library
(addition, subtraction, multiplication, division, comparison, sin/cos/log, and conversions to and from ints) will take.
On the flip side, I'd be happy with 2MHz Z80-class speeds, to tell the truth, and we have a fair number of MIPs to work with
here, so we'll have to see.
It will definitely take some cleverness. Which is all a large part of the fun.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Imagine, being able to store every 8-Bit Atari program ever written in a single 256 MB CF card - which happens to be a side project I'm working on now.
Hmmm....The crystal I pulled from my board was labeled 1.000MHz. One of those big 1 inch wide jobs. Anyway it matters not.
The point I was trying to make was that the Propeller has quite a bit more horse power under the hood and deserves a class of
it's own to accurately depict what it is and is not capable of. As it has been mentioned earlier, when the Propeller was designed
the conventional way of thinking was thrown out the window, so unless someone can equate apples to oranges, there is really
no suitable comparison.
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
As for the interrupt topic. Interrupts can be both the best and worst of development. In my early embedded 8086 systems, a well coded interrupt eliminated the need for a RTOS. There were many machine tools I developed that were completely interrupt driven. Yur right, documentation on how to write interrupt handlers is typically way too involved. But a part if that is due to all the potential gotchas that await writing interrupts.
I double checked the Atari 400/800 Hardware manual and there's actually a 3.57 MHz crystal in the computer and the 6502 CPU runs at half the crystal speed, or 1.79 MHz. I think you confused the Atari 400/800 with the Apple II - which has a 1.0 MHz 6502.
I'd like to express interest in this, and I hope that it becomes a reality. I'm sure that it would be useful to many.
Rick
Your right! 1.79MHz ....Somehow in 27 years I lost 790kHz
www.vintage-computer.com/atari_800.shtml
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
I think that was the famous Dr. Dobb's Journal 'Tiny Basic' for the 6502 [noparse][[/noparse]about 1987].
The speed thing is more about 'whiz bang' in game applications than about writing a novice Basic Program. I imagine Graphics will suck up a tremendous about of RAM or EEPROM.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
You've only lost 790 khz - but I've lost a lot more hair!
The same friend and I used to joke about Microsoft's ability to crank out a BASIC Interpreter for just about any chip on the market. We assumed they just loaded the opcodes into a big VAX and the prom would pop out the other end. Maybe someone at Microsoft still knows where that VAX is in the basement out in Redmond.
--Paul
FYI: My 7 y/o loves it when I boot the C64 system... There are so manay games he likes to play, and the SIDS (Commodore's equ to Mp3's)...
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Just tossing my two bits worth into the bit bucket
KK
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