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R800 Creator

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By Necron

Guardian (129)

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15-09-2003, 18:22

Hello...
I'm sorry about this possible stupi question... I've reserched about it at Google without success...

Does anyone in here knows who have created the R800?
And why the Ascii decided to use this processor instead os using any from Zilog? (I know that there are some fans of the R800. I am not saying that I am against it, I just want to understand the decision Smile )
Do you know any history about the R800? (Or where to find it?)

Thanks!
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By DarQ

Paladin (844)

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15-09-2003, 18:57

# R800 made by Ascii Japan, used for MSX Turbo R (made by Panasonic)

z80.info/zip/r800.zip

By GuyveR800

Prophet (3057)

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15-09-2003, 19:24

It was developed by ASCII in cooperation with Toshiba, and also manufactured by Toshiba. (As with many of the MSX chips)

By Necron

Guardian (129)

Necron's picture

15-09-2003, 20:45

So the Ascii itself have created the r800... (ok, and Toshiba)
I can assume in here so, that no other computer system have ever used this microprocessor, differently from z80, right? It was exclusive to msx?

But still... Why they have chosen to build their own microprocessor, instead of using some sucessor of Z80 from Zilog? (I don't know what M.P. were available by Zilog that year. But I've read somewhere that the Z380 was released one year later... That would be a wonderfull choice... but one year would be too much to wait... The TurboR itself was released too late, they couldn't wait any longer, right?) Anyway, they could use any other options available, don't they?

By the way: I don't have any problems at all with R800... I'm just very curious about their attitude in changing their cpu "distributor" ehhe Smile

Do you have any idea why that happened?

By Algorythms

Master (179)

Algorythms's picture

15-09-2003, 21:10

Oi! Actually they used the R800 in some Toshiba stuff like Printers and Copiers.
And supposedly in the "Toshiba TurboR" which was used in hospitals in Japan.
-Dan

By Necron

Guardian (129)

Necron's picture

15-09-2003, 21:14

Cool!
The Z80 is still manufactured by Zilog (and its sucessors)... Is the r800 still being in the production line to be used in some mini-game, or printer, or stuff nowadays?

By GuyveR800

Prophet (3057)

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16-09-2003, 00:53

AFAIK R800 is not being produced at this moment. Toshiba has a very nice 32 bit redesigned version of the Z80 processor, used in e.g. Neogeo Pocket.

IIRC, Z380 was only released in 1994, 4 years after R800 was designed.

By Necron

Guardian (129)

Necron's picture

16-09-2003, 17:10

4 years? ok, my source of information didn't seem very trustable anyway Smile

Now I came up with a thinking... If th R800 is assembly compatible with Z80, with the Turbo-R come with the two of them???

By GuyveR800

Prophet (3057)

GuyveR800's picture

16-09-2003, 17:47

R800 cycle times are completely different from Z80. A lot of MSX products are sensitive to exact timing. Also, some programs use undocumented instructions of Z80 that are not available in R800 (most notably 'SLI' instruction).
Even if you make R800 run at 3.58MHz, it will still be faster, which can cause problems.

By Necron

Guardian (129)

Necron's picture

16-09-2003, 20:50

So, where is the advantage in having the R800 compatible with Z80?

By SjaaQ

Resident (39)

SjaaQ's picture

16-09-2003, 21:21

So you can run your "old" software on a "new" computer? This is the same with the I8086 and above. You can still run old I8086 software on a Pentium IV...
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