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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: nicholas on April 09, 2013, 08:12:18 PM
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These pages describe Kiwi, a Motorola MC68008-based computer system which was developed and built as a hobby. The intention was rather to start another FPGA based project, but to design a classic computer with dedicated controllers and a count of 74 TTL chips. As for design, the goal was to create a computer system which could have existed in the 80ies. As for a typical homecomputer, the system needs some kind of input, output and mass storage. With this in mind, I started to draw schematics and created the printed circuit board (PCB) layout. In respect to the design goal, old and obsolete chips were not excluded, whereby chip brookers helped to get all needed parts. The PCB has been manufactured from my layout data by PCB-Pool (http://www.pcb-pool.de/). After soldering, I began porting Lee Davison's Enhanced Basic 68k (http://mycorner.no-ip.org/68k/ehbasic/index.html) to Kiwi. A Basic interpreter, which is free for personal or educational use. First, with interaction via a serial connection. Over the time, I wrote routines for the video controller and the keyboard interface. When the system ran stand-alone, I proceeded adding more functions. I ported an freely (GPL (http://www.ist-schlau.de/gpl-2.0.txt)) available FAT filesystem library (http://ultra-embedded.com/?fat_filelib) as well as a freely (BSD License (http://www.xfree86.org/3.3.6/COPYRIGHT2.html#5)) available TCP/IP stack (http://savannah.nongnu.org/projects/lwip/).
For the future, my plans are to program some simple games.
Specifications:
CPU MC68008, clocked with 10MHz
RAM4MB DRAM, 512kB dedicated VRAM VideoYamaha V9990 Video Display Processor
Audio dual SID stereo (MOS6581 or MOS8580)
Mass storage IDE/ATA and floppy disk interface (WD177x)
Time/Date Realtime clock Epson RTC72421
Network 10base-T Ethernet (CS8900a)
Interfaces PS/2 compatible Keyboard and Mouse ports
Two Atari style Joystick ports
RS232 and parallel ports
ROM32KB EPROM with IDE/ATA Boot Code
Operating system Enhanced Basic 68k (http://mycorner.no-ip.org/68k/ehbasic/index.html)
http://www.ist-schlau.de/
https://www.youtube.com/user/Bogog75?feature=watch
Just needs a nice lightweight operating system like AROS methinks! :)
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Lovely, but why a 68008? Kamelito
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aros is still everything else than lightweight im afraid. it would hardly be a pleasure to run it on 68000 class cpu. more work is needed and more involved experienced coders. sorry to say.
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aros is still everything else than lightweight im afraid. it would hardly be a pleasure to run it on 68000 class cpu. more work is needed and more involved experienced coders. sorry to say.
AROS is still more lightweight than Linux ;)
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Man, for dual SID I'd almost put up with the crippling performance issues that a 68008 would bring.
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Simply outstanding!!!
I see lots of dedication and passion in this project. Amazing work!
Thanks for sharing.
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Is this the one in Radio and Electronics Magazine in the late '80s?
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(Audio dual SID stereo (MOS6581 or MOS8580))
I can see many a poor defenceless 64 being raped of their voice.
The idea of the machine is intriguing though....
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You can easily find LOT of SID chips without removing from working C64's.
Other devices uses SID chips like MidiBox SID, SammichSID etc.
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You can easily find LOT of SID chips without removing from working C64's.
Other devices uses SID chips like MidiBox SID, SammichSID etc.
Easily? No. For a cost yes, but there isn't a 'LOT' of them spare out there.
I'm well aware of the Midibox, SID station, hardSID etc.
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from Wiki:
To support lower-cost systems and control applications with smaller memory sizes, Motorola introduced the 8-bit compatible MC68008, also in 1982. This was a 68000 with an 8-bit data bus and a smaller (20 bit) address bus. After 1982, Motorola devoted more attention to the 68020 and 88000 projects.
So...an MC68008 is actually an even crappier version of the 68000. Sign me up :rolleyes:
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Yeah, that's what baffles me here - the 68000 had enough performance issues on a 16-bit bus!
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Lovely, but why a 68008? Kamelito
1. less tracks on the board.
2. you can use one 8 bit rom to boot from rather than two or a 16 bit rom.
3. simpler ram interface logic.
I don't have a problem with 68008, but a couple of VIC IIs would have been more interesting.
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from Wiki:
To support lower-cost systems and control applications with smaller memory sizes, Motorola introduced the 8-bit compatible MC68008, also in 1982. This was a 68000 with an 8-bit data bus and a smaller (20 bit) address bus. After 1982, Motorola devoted more attention to the 68020 and 88000 projects.
So...an MC68008 is actually an even crappier version of the 68000. Sign me up :rolleyes:
The 68008 is for small, cheap, easy to program processor for embedded, hobby and educational projects. It's still a full 68000 inside but has less external wires to mess with or pay for. Think of a processor for something like a keyboard. It is still more powerful and easier to program that a 6502 for example. Availability is a problem though. There was a college in Ireland that was using the 68008 with breadboards for college courses and made an fpga version when the 68008 productions stopped. The 68008 is rather weak for a main CPU considering the other add-ons. A Fido or ColdFire wouldn't be much more expensive and makes more sense in a lot of ways.
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@nicholas
Really nice looking project. I wish I had your skills.
Just one question. You use a 68008 and say you have 4MB RAM. Since the 68008 only has 20 address bits, are you using bank switching for this?
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This project sounds like a somewhat crippled remake of the Sharp X68000.
http://en.wikipedia.org/wiki/Sharp_X68000
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Just one question. You use a 68008 and say you have 4MB RAM. Since the 68008 only has 20 address bits, are you using bank switching for this?
The 68008 is available in 48 pin & 52 pin versions. The later has 22 address lines.
There is also the 68hc001, which is the replacement for the 68008 and can run in either 8 or 16 bit mode & has 24 address lines.
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After checking the cool youtube vids out, it looks like it was just a one-off by a very talented guy just for fun. The telnet client vid was neat - especially the refresh rate for top :D
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So...an MC68008 is actually an even crappier version of the 68000. Sign me up :rolleyes:
Yes, why didn't he put an Intel Core i7 on it? I mean, most things are crappier. :rolleyes:
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If speed was really such a concern to any of us, why would we be using Amigas at all?
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It's a nice project, ramming together all the 80s machines.
68008 from the Sinclair QL.
V9990 is an enhanced version of the MSX2+ graphics chip (the chip was produced in the early 90s though).
SIDs from the C64.
I'd say the next step would be to use a full 68000, that 8-bit data bus is going to be holding the CPU back.
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If speed was really such a concern to any of us, why would we be using Amigas at all?
I don't think people are concerned the device will be slow, that's a given. The problem is that the 8bit bus will artificially limit the CPU for no really good reason.
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I don't think people are concerned the device will be slow, that's a given. The problem is that the 8bit bus will artificially limit the CPU for no really good reason.
How is that an artificial limitation? The bus is a very tangible and real limitation for any CPU, boo-hoo.
Tell me, if they used a 68000, what would suffice as a "good reason" for that choice?
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How is that an artificial limitation? The bus is a very tangible and real limitation for any CPU, boo-hoo.
There are no 68000 instructions that are only one byte long. They are all a multiple of 2 bytes.
So a byte wide bus means you need to use at least 2 extra cycles per instruction on a 68008 compared to a 68000. If it makes your machine easier to construct then by all means go for it, but it is like tieing one hand on your back.
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There are no 68000 instructions that are only one byte long. They are all a multiple of 2 bytes.
So a byte wide bus means you need to use at least 2 extra cycles per instruction on a 68008 compared to a 68000. If it makes your machine easier to construct then by all means go for it, but it is like tieing one hand on your back.
I know that, but it still doesn't answer my question.
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@nicholas
Really nice looking project. I wish I had your skills.
Just one question. You use a 68008 and say you have 4MB RAM. Since the 68008 only has 20 address bits, are you using bank switching for this?
Oh, it's not my creation, I wish I had the skills! :)
I just posted it here as I thought people might find it interesting.
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How is that an artificial limitation? The bus is a very tangible and real limitation for any CPU, boo-hoo.
Tell me, if they used a 68000, what would suffice as a "good reason" for that choice?
I said "artificial limit" because the 68000 works best with a 16bit bus.
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I said "artificial limit" because the 68000 works best with a 16bit bus.
What does that have to do with the 68008? The 68008 works best with an 8-bit bus. There is no artificial limit imposed.
Seriously, the thing runs a line number BASIC editor, has a VDP from the early 90s, and a couple of buggy sound chips from the 80s, and the first thing you can think of as "artificially limited" is the CPU? It's a dated and inefficient design, but that's obviously the whole point of the project. If he wanted to build a computer without "crippling performance issues" he wouldn't have used any CPU from the 68k series.
So I think you should all stop whining about a few extra cycles spent on memory reads and realize that in terms of performance, the 68000 and the 68008 are two drops in the bathtub you get when if buy a decent cell phone. Whatever argument you are making, it could as well escalate into "why not a 68020", "why not a Coldfire", "why not an ARM" or "why not Intel". But it doesn't, because you have no sense of scale.
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What does that have to do with the 68008? The 68008 works best with an 8-bit bus. There is no artificial limit imposed.
Seriously, the thing runs a line number BASIC editor, has a VDP from the early 90s, and a couple of buggy sound chips from the 80s, and the first thing you can think of as "artificially limited" is the CPU? It's a dated and inefficient design, but that's obviously the whole point of the project. If he wanted to build a computer without "crippling performance issues" he wouldn't have used any CPU from the 68k series.
So I think you should all stop whining about a few extra cycles spent on memory reads and realize that in terms of performance, the 68000 and the 68008 are two drops in the bathtub you get when if buy a decent cell phone. Whatever argument you are making, it could as well escalate into "why not a 68020", "why not a Coldfire", "why not an ARM" or "why not Intel". But it doesn't, because you have no sense of scale.
WOW! Now that people is what we call a sass! Though, I have to admit you are right 100%.
The guy just made a toy...it is a toy..really. It may be a Commodore 65 duplicate without us knowing. Personally I will buy it instead of gp2x or Nintendo DSi, or PSP. I consider it an entertainment system, a console and so forth so I will buy it for the games it will be developed for it. The graphics are great it have potential of having awesome sweet (good quality graphics) games like SNES, Genesis etc....so why not? I will buy it.
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So I think you should all stop whining about a few extra cycles spent on memory reads and realize that in terms of performance, the 68000 and the 68008 are two drops in the bathtub you get whenif buy a decent cell phone.
I know it may make you feel very clever to compare one-off hobby projects or any non-cellphone platform that contains an ARM chip to a cell phone, but it just comes across as ignorant. A smartphone is not a general purpose computer, even if its quad core and running at 1.6Ghz+.
When I read the OP, it made it seem as if this guy was going to do a production run of underpowered 8bit-ish "hobby" computers. I suppose if assembling one for the express purpose of saying you did is your thing, then all the power to you. What I find hilarious is that a one-off 8 bit hobby computer is able to have even basic network connectivity, where here in amigaland is only possible in an easy sense if you have an amiga with PCMCIA. While some may find projects like this inspiring, I just find them sad that we have no hardware guys able to shoehorn some easily available componentry into our miggys for a reasonable price (besides Jens, and I don't really consider his prices all that reasonable, even if his hardware is nice).
More and more it seems Amiga, if compared to comic books, is not the series you enjoy to read and dog ear your favorite pages, but more the series you buy off the shelf, stick in an acid free sleeve and bring out to sell later on when you need a new bathroom.
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When I read the OP, it made it seem as if this guy was going to do a production run of underpowered 8bit-ish "hobby" computers. I suppose if assembling one for the express purpose of saying you did is your thing, then all the power to you. What I find hilarious is that a one-off 8 bit hobby computer is able to have even basic network connectivity, where here in amigaland is only possible in an easy sense if you have an amiga with PCMCIA. While some may find projects like this inspiring, I just find them sad that we have no hardware guys able to shoehorn some easily available componentry into our miggys for a reasonable price.
More and more it seems Amiga, if compared to comic books, is not the series you enjoy to read and dog ear your favorite pages, but more the series you buy off the shelf, stick in an acid free sleeve and bring out to sell later on when you need a new bathroom.
Amen!
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It's a nice project, ramming together all the 80s machines.
68008 from the Sinclair QL.
V9990 is an enhanced version of the MSX2+ graphics chip (the chip was produced in the early 90s though).
SIDs from the C64.
I'd say the next step would be to use a full 68000, that 8-bit data bus is going to be holding the CPU back.
68000 would be nice.
Personally I'd be interested in a similar machine based around an Hitachi 6309.
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I know it may make you feel very clever to compare one-off hobby projects or any non-cellphone platform that contains an ARM chip to a cell phone, but it just comes across as ignorant.
How so? If you're bent on computational performance, you have no business looking at 80s CPUs. The comparison is completely valid from a performance perspective.
A smartphone is not a general purpose computer, even if its quad core and running at 1.6Ghz+.
Not calling a smartphone a general purpose computer shows your complete ignorance of the meaning of the term. I might have agreed if you said that they're not "modular computers" or "open computers" but they are very much general purpose.
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How so? If you're bent on computational performance, you have no business looking at 80s CPUs. The comparison is completely valid from a performance perspective.
Its a spurious and silly comparison. "OMG it can't outperform teh Droid phonez!" is not what the critique was about. A standard 68000 or 68010 has 64 pins - that's hardly an unmanageable amount of pins. If 8 bit is all that is wanted, fine - the 68008 is perfectly fine.
Not calling a smartphone a general purpose computer shows your complete ignorance of the meaning of the term. I might have agreed if you said that they're not "modular computers" or "open computers" but they are very much general purpose.
This forum and amigans in general are fans of making retarded cellphone comparisons whenever performance or architecture things are brought up (rpi, odroid, ouya, etc etc), as if I can take my cellphone and easily install any operating system I want, utilize the bus to drive additional hardware, install keyboards and mice and larger screens easily, install whatever software I want easily, compile on it, etc. They are not general purpose, they are radio receivers that also allow you some compute functionality.
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Its a spurious and silly comparison. "OMG it can't outperform teh Droid phonez!" is not what the critique was about. A standard 68000 or 68010 has 64 pins - that's hardly an unmanageable amount of pins. If 8 bit is all that is wanted, fine - the 68008 is perfectly fine.
I'm not saying "OMG it can't outperform teh Droid phonez!". I'm saying that dismissing what is so obviously a hobbyist system not meant to compete in terms of performance in any way whatsoever on the basis of bad performance compared to a slightly faster stone-age CPU is totally ridiculous. Just as ridiculous as bringing ARMs to the table.
And of course he wanted an 8-bit bus. Would he blindly pick a CPU and build a working system around it not knowing its bus width?
This forum and amigans in general are fans of making retarded cellphone comparisons whenever performance or architecture things are brought up (rpi, odroid, ouya, etc etc), as if I can take my cellphone and easily install any operating system I want, utilize the bus to drive additional hardware, install keyboards and mice and larger screens easily, install whatever software I want easily, compile on it, etc. They are not general purpose, they are radio receivers that also allow you some compute functionality.
General purpose computers existed long before computer keyboards, mice, large screens and compilers. Those things are totally irrelevant to the concept of general purpose computers, but sure, I get what you are trying to say. You just aren't familiar with the terminology.
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General purpose computers existed long before computer keyboards, mice, large screens and compilers. Those things are totally irrelevant to the concept of general purpose computers, but sure, I get what you are trying to say. You just aren't familiar with the terminology.
Sure, they are called brains. Hell, throw in the abacus, the slide rule and Babbage's Difference engine. You are just being pedantic and argumentative. So, try not throwing out cellphone analogies (they don't fit), blindly jumping from single core CISC chips lacking mmu/fpu/pipelining/superscalar architectures (at least in the 68000 area) to quad core RISC architectures to prove some lame point about "power", and making non-relevant asides about fictitious "concepts" of "general purpose" computers... unless you have a link to an academic paper backing your snobbery up, that is - in which case I would be more than happy to read it.
EDIT: I wonder if it can run OS4:
[youtube]KlRoZ0zTXvw[/youtube]
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Sure, they are called brains. Hell, throw in the abacus, the slide rule and Babbage's Difference engine. You are just being pedantic and argumentative. So, try not throwing out cellphone analogies (they don't fit), blindly jumping from single core CISC chips lacking mmu/fpu/pipelining/superscalar architectures (at least in the 68000 area) to quad core RISC architectures to prove some lame point about "power", and making non-relevant asides about fictitious "concepts" of "general purpose" computers... unless you have a link to an academic paper backing your snobbery up, that is - in which case I would be more than happy to read it.
Haha, do you doubt the fact that general purpose computing is a concept? Maybe you could link to an academic paper supporting your idea that cellphone analogies don't fit. Maybe that idea just based on a totally arbitrary threshold that only exists in your head.
But hey let's talk single core CISC. Pentium III?
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This forum and amigans in general are fans of making retarded cellphone comparisons whenever performance or architecture things are brought up (rpi, odroid, ouya, etc etc), as if I can take my cellphone and easily install any operating system I want, utilize the bus to drive additional hardware, install keyboards and mice and larger screens easily, install whatever software I want easily, compile on it, etc. They are not general purpose, they are radio receivers that also allow you some compute functionality.
http://forum.xda-developers.com/showthread.php?t=889433 ;)
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Haha, do you doubt the fact that general purpose computing is a concept? Maybe you could link to an academic paper supporting your idea that cellphone analogies don't fit. Maybe that idea just based on a totally arbitrary threshold that only exists in your head.
But hey let's talk single core CISC. Pentium III?
I Will! Just as soon as I get it published in "Cantankerous Gits Monthly" along with a paper I have in mind about low slung jeans and that crappy Hippity Hop music. Git Offah Mah Lawn!
Here I am responding to Nicholas' link to the Ubuntu Phone Edition link:
(http://www.wpclipart.com/cartoon/people/men_cartoons/old_men/cranky_old_man.png)
Kids these days - BAH!
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... The 68008 is rather weak for a main CPU considering the other add-ons. A Fido or ColdFire wouldn't be much more expensive and makes more sense in a lot of ways.
I like the idea of a simple Coldfire system.
Using a PCI video card like a Voodoo3 the system could be powerful enough for an AROS port.
In fact, much of the work done on the 68K version should be easy to re-write.
I have two 200MHz Coldfire CPUs that support PCI. They only cost about $20.
233MHz versions run about $25.
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So a byte wide bus means you need to use at least 2 extra cycles per instruction on a 68008 compared to a 68000. If it makes your machine easier to construct then by all means go for it, but it is like tieing one hand on your back.
I'm not sure. For most instructions the 68000 only accesses the bus every two cycles, where it fetches 2 bytes. I am too lazy to check, but it would not surprise me if the 68008 accesses the bus on every cycle. So it might not make much difference.
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...
Personally I'd be interested in a similar machine based around an Hitachi 6309.
That would interest me too.
I have three 63C09s sitting in my spare parts bin (and another installed in an Atari 130XE).
I looked at the predecessor of that Yamaha VDP years ago.
They have overlay and sprite support.
How about multiple 63C09Es running at 3.56 MHz with interleaved memory access? After all, really fast memory is available, and with individual caches the processors could all share the same memory.
SIDs tied to a multitasking system with decent graphics?
Sounds neat.
And I can handle 6809/6309 assembly code.
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Yes, why didn't he put an Intel Core i7 on it? I mean, most things are crappier. :juggler:
Yes. Great suggestion.
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@psxphill
Oh cool. I didn't know that. Still a brilliant achievement.
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I like the idea of a simple Coldfire system.
Using a PCI video card like a Voodoo3 the system could be powerful enough for an AROS port.
In fact, much of the work done on the 68K version should be easy to re-write.
I have two 200MHz Coldfire CPUs that support PCI. They only cost about $20.
233MHz versions run about $25.
The ColdFire is nice because of the SoC capabilities which are old but fine for a hobby project. The Fido is actually more interesting to me as a CPU and I'm surprised no hobbyists have tried to do anything with it. My main Amiga is a 68060@75MHz with Mediator+Voodoo 4. Despite the slow PCI gfx bus (~8 MB/s), I can load Quake in about 30 seconds and get about 25 fps in 640x480x16 full screen with QuakeGL. I think 30fps would be possible with more optimized code. That's not bad for 90s era hardware ;).
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"68000 would be nice.
Personally I'd be interested in a similar machine based around an Hitachi 6309."
You could just buy a tandy color computer III and the 6309 is pin to pin compatible with the 6809 and twice as fast. Many people have done this. I believe someone also interfaced sid chips to the coco... I have a 6309 coco.
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I Will! Just as soon as I get it published in "Cantankerous Gits Monthly" along with a paper I have in mind about low slung jeans and that crappy Hippity Hop music. Git Offah Mah Lawn!
Here I am responding to Nicholas' link to the Ubuntu Phone Edition link:
(http://www.wpclipart.com/cartoon/people/men_cartoons/old_men/cranky_old_man.png)
Kids these days - BAH!
:lol:
Not been referred to as a kid for many a decade, I'll be happy all day now. :)
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"68000 would be nice.
Personally I'd be interested in a similar machine based around an Hitachi 6309."
You could just buy a tandy color computer III and the 6309 is pin to pin compatible with the 6809 and twice as fast. Many people have done this. I believe someone also interfaced sid chips to the coco... I have a 6309 coco.
I've always found the Coco an interesting machine, it's quite exotic here in Blighty. The Dragon series was our nearest equivalent I think.
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That would interest me too.
I have three 63C09s sitting in my spare parts bin (and another installed in an Atari 130XE).
I looked at the predecessor of that Yamaha VDP years ago.
They have overlay and sprite support.
How about multiple 63C09Es running at 3.56 MHz with interleaved memory access? After all, really fast memory is available, and with individual caches the processors could all share the same memory.
SIDs tied to a multitasking system with decent graphics?
Sounds neat.
And I can handle 6809/6309 assembly code.
If only I had the skills to build such a beast! :(
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I'm not sure. For most instructions the 68000 only accesses the bus every two cycles, where it fetches 2 bytes. I am too lazy to check, but it would not surprise me if the 68008 accesses the bus on every cycle. So it might not make much difference.
That would be reasonable, but I always thought the 68008 was just an ordinary 68000 with only 8data lines exposed, thus is would also suffer the every other cycle memory access penalty.
-Edit- But actually thinking about it, that would make almost all the addressing modes pointless...
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I'd love to try that Hitachi CPU!
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Is it named Kiwi in honour of Trevor?
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That would be reasonable, but I always thought the 68008 was just an ordinary 68000 with only 8data lines exposed, thus is would also suffer the every other cycle memory access penalty.
It's not just a 68000 with 8 data lines, it has a0 as well.
My point about the speed was that on the 68000 it would read a word at cycle 0, cycle 2, cycle 4 etc. While the 68008 may read a byte on cycle 0, cycle 1, cycle 2, cycle 3 etc. So as long as you don't require access to the bus then it's the same.
If you did need to dma from memory as well as fetching then you could use 16 bit ram and buffer words and allow the second byte to be read from the buffer. However you're getting into being easier to just use a 68000. These days you could probably just use vram or double speed ram as well.
A 68SEC000 is probably the best bet & it can be clocked really fast, but the bus can also be configured as 8 bit or 16 bit. MOVE SR is privileged though, which makes it more like a 68010.
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Motorolla claimed the 68008 was 30% slower than the 68000 at the same clock speed, which seems an acceptable price to pay for the simpler and cheaper 8 bit computer design it made possible.