| The best 8-bit computer Commodore ever made was... the MPS1200! [message #208978] |
Mon, 08 August 2011 12:12  |
Chris Baird
Messages: 172
Registered: December 2011
Karma: 0
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Senior Member |
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I don't think it's ever been mentioned: the IEC controller board
included with the MPS1200 printer has a very swweeeett 6502-derived
microcontroller on it-- a Mitsubishi M50734!
The M50734 runs at 8MHz, has 36 I/O pins, a /DME signal for addressing a
second 64kB bank of memory, seperate /R and /W signals that anyone who
has done 8-bit IDE drive interfacing will know is a win, and the
Mitsubishi 740-series 6502-compatible instruction set, extra addressing
modes, and extra status mode bits[!!!]...which makes the 65C02 family
look totally half-arsed by comparison.
After removing the IEC controller board, wiring the RESET pin 11 of CN11
to ground, supplying 5V to CN11.30, ground to CN11.15, and dropping your
own 27C512 EPROM, you've got _very_ neat kit/embedded computer to play
with.. (And it's not that Harvard-architecture crap in the Arduino!)
So, I'm building a /fast/ (faster than the first Amiga?) Commodore
6502 computer around the MPS1200's IEC board. The board comes with just
a 8kB SRAM chip, but that's only for the moment, and easy-enough hacked
around.. The MPS1250 has a similiar board, but with a 128kB EPROM.
No hand-holds, no howtos, no webpage, no code, no products.. I've
successfully got the obligatory "LED Flashing" code at
http://pastebin.com/AQ4bfUeE running.. Early days. The IEC controller's
ROM has been fully disassembled as well, and a friend and I are looking
to get the 740 support I've written added to the mainline da65 source,
and possibly the rest of cc65..
--
Chris
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| Re: The best 8-bit computer Commodore ever made was... the MPS1200! [message #208983 is a reply to message #208978] |
Tue, 09 August 2011 07:58  |
Clocky
Messages: 1212
Registered: December 2011
Karma: 0
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Senior Member |
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Chris Baird wrote:
> I don't think it's ever been mentioned: the IEC controller board
> included with the MPS1200 printer has a very swweeeett 6502-derived
> microcontroller on it-- a Mitsubishi M50734!
>
> The M50734 runs at 8MHz, has 36 I/O pins, a /DME signal for
> addressing a second 64kB bank of memory, seperate /R and /W signals
> that anyone who has done 8-bit IDE drive interfacing will know is a
> win, and the Mitsubishi 740-series 6502-compatible instruction set,
> extra addressing modes, and extra status mode bits[!!!]...which makes
> the 65C02 family look totally half-arsed by comparison.
>
> After removing the IEC controller board, wiring the RESET pin 11 of
> CN11 to ground, supplying 5V to CN11.30, ground to CN11.15, and
> dropping your own 27C512 EPROM, you've got _very_ neat kit/embedded
> computer to play with.. (And it's not that Harvard-architecture crap
> in the Arduino!)
>
> So, I'm building a /fast/ (faster than the first Amiga?) Commodore
> 6502 computer around the MPS1200's IEC board.
What makes you think any 6502 computer could hope to compete with the
glorious Amiga chipset?
The board comes with
> just a 8kB SRAM chip, but that's only for the moment, and easy-enough
> hacked around.. The MPS1250 has a similiar board, but with a 128kB
> EPROM.
>
> No hand-holds, no howtos, no webpage, no code, no products.. I've
> successfully got the obligatory "LED Flashing" code at
> http://pastebin.com/AQ4bfUeE running.. Early days. The IEC
> controller's ROM has been fully disassembled as well, and a friend
> and I are looking to get the 740 support I've written added to the
> mainline da65 source, and possibly the rest of cc65..
Sounds very interesting, are you planning to document and show some pics
etc?
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| Re: The best 8-bit computer Commodore ever made was... the MPS1200! [message #208986 is a reply to message #208978] |
Wed, 10 August 2011 04:19 |
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Originally posted by: Merman
On Aug 8, 5:12 pm, Chris Baird <ab...@brushtail.apana.org.au> wrote:
> I don't think it's ever been mentioned: the IEC controller board
> included with the MPS1200 printer has a very swweeeett 6502-derived
> microcontroller on it-- a Mitsubishi M50734!
>
> The M50734 runs at 8MHz, has 36 I/O pins, a /DME signal for addressing a
> second 64kB bank of memory, seperate /R and /W signals that anyone who
> has done 8-bit IDE drive interfacing will know is a win, and the
> Mitsubishi 740-series 6502-compatible instruction set, extra addressing
> modes, and extra status mode bits[!!!]...which makes the 65C02 family
> look totally half-arsed by comparison.
>
> After removing the IEC controller board, wiring the RESET pin 11 of CN11
> to ground, supplying 5V to CN11.30, ground to CN11.15, and dropping your
> own 27C512 EPROM, you've got _very_ neat kit/embedded computer to play
> with.. (And it's not that Harvard-architecture crap in the Arduino!)
>
> So, I'm building a /fast/ (faster than the first Amiga?) Commodore
> 6502 computer around the MPS1200's IEC board. The board comes with just
> a 8kB SRAM chip, but that's only for the moment, and easy-enough hacked
> around.. The MPS1250 has a similiar board, but with a 128kB EPROM.
>
> No hand-holds, no howtos, no webpage, no code, no products.. I've
> successfully got the obligatory "LED Flashing" code athttp://pastebin.com/AQ4bfUeErunning.. Early days. The IEC controller's
> ROM has been fully disassembled as well, and a friend and I are looking
> to get the 740 support I've written added to the mainline da65 source,
> and possibly the rest of cc65..
>
> --
> Chris
Great, but don't give the credit to Commodore. They simply rebadged an
Epson printer and added the IEC port...
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| Re: The best 8-bit computer Commodore ever made was... the MPS1200! [message #208998 is a reply to message #208992] |
Fri, 12 August 2011 04:53 |
Clocky
Messages: 1212
Registered: December 2011
Karma: 0
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Senior Member |
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RobertB wrote:
> On Aug 8, 9:12 am, Chris Baird <ab...@brushtail.apana.org.au> wrote:
>
>> I don't think it's ever been mentioned: the IEC controller board
>> included with the MPS1200 printer has a very swweeeett 6502-derived
>> microcontroller on it-- a Mitsubishi M50734!
>
> Hmm, I have a couple of MPS-1200's, and they
> are just sitting there unused. I never thought about
> opening them up and using the chips within them.
>
> Good idea!
I think it may be a bit beyond your skillset...
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| Re: The best 8-bit computer Commodore ever made was... the MPS1200! [message #209000 is a reply to message #208978] |
Fri, 12 August 2011 09:36 |
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Originally posted by: KB777
On 8 Sie, 18:12, Chris Baird <ab...@brushtail.apana.org.au> wrote:
> I don't think it's ever been mentioned: the IEC controller board
> included with the MPS1200 printer has a very swweeeett 6502-derived
> microcontroller on it-- a Mitsubishi M50734!
Well, Renesas did not drop the 740 family yet, but they discarded the
7700 line (?) - which was 65c816 derived IMHO (I remember 37702 at 25
MHz or something in my old Sony CDU55e 2x CDROM drive years ago, also
came across some 740/7700 MCU at several places...).
Right now I have another nice 65(x)02 based stuff on my desk - some
modem units a CX81300 - 65c02@28 MHz with external 0-waitstate 15 ns
SRAM (32kB) and 29f010 FLASH. Unfortunately the wait states for
external ROM seem to be fixed to 4 clocks, still this a nice thing to
play with ;)
Regards,
Konrad
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| Re: The best 8-bit computer Commodore ever made was... the MPS1200! [message #209004 is a reply to message #208984] |
Sun, 14 August 2011 08:40 |
Mark McDougall
Messages: 124
Registered: March 2008
Karma: 0
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Senior Member |
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On 9/08/2011 10:18 PM, Chris Baird wrote:
>>> So, I'm building a /fast/ (faster than the first Amiga?) Commodore
>>> 6502 computer around the MPS1200's IEC board.
>
>> What makes you think any 6502 computer could hope to compete with the
>> glorious Amiga chipset?
>
> 68000
> using up to 88 cycles for an interrupt
(sarcasm)
Yeah, because that's _really_ what's important for general applications...
(/sarcasm)
--
| Mark McDougall | "Electrical Engineers do it
| <http://members.iinet.net.au/~msmcdoug> | with less resistance!"
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| Re: The best 8-bit computer Commodore ever made was... the MPS1200! [message #209160 is a reply to message #208978] |
Thu, 15 September 2011 12:10 |
sjgray
Messages: 53
Registered: April 2012
Karma: 0
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Member |
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On Aug 8, 12:12 pm, Chris Baird <ab...@brushtail.apana.org.au> wrote:
> I don't think it's ever been mentioned: the IEC controller board
> included with the MPS1200 printer has a very swweeeett 6502-derived
> microcontroller on it-- a Mitsubishi M50734!
Very nice. I picked up a couple of those chips off ebay at a
reasonable price. I would be interested in seeing what you can do with
it. There are MPS1200 schematics on the web as well for those that
want to build something based on this chip.
Steve
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