external Z80B

Resident (48)

25-02-2007, 16:07

hallo,

I was tidying up my room this morning and I have come across an old
italian Magazine.( C16-MSX nr.38 year 1990)
There's an article wich talks about an Interface (developed by a Nederland Hardware House) to Speed up MSX2 to 7 Mhz.

Probably the reporter was too vague and I have not understood very well.

but ,Now, my questions are :

1) Pin description of Cartridge connectors shows that there are two
reserved line (Pin 5 , Pin 16 What are they for? )
2) There is no BUSAK and no BUSREQ , so how can exist two Z80.CPUs at the same time without conflict?
3) Are BUSAK and BUSREQ implemented on some MSX1/2 machine?

Thanks for your attention..

By legacy

Hero (570)

25-02-2007, 17:35

I think that you are refer to a 7 mhz update kit, but this is not a cartridge.

More info at www.hansotten.com/msxdiy.html almost on the bottom of this page.

By monant

Resident (48)

25-02-2007, 22:17

thanks for replying,

Yes ,I have already visited this very interesting site many times
and I think the kit you 're talking about needs the Z80 on the motherboard and other components to be removed and replaced.....

the article I quoted above was not so detailed.....

Anyway , I'll take advantage of your patience
could anybody satisfy my curiosity about
answer 1,2,3 ?

By Edwin

Paragon (1182)

25-02-2007, 23:12

2) Because there actually can't.

(no hardware knowledge, so can't answer your other questions)

By legacy

Hero (570)

25-02-2007, 23:24

I think the kit you 're talking about needs the Z80 on the motherboard and other components to be removed and replaced.....

That's corrrect.
I did that update by myself, longtime ago, and it's still working great.

By Manuel

Ascended (19468)

26-02-2007, 11:51

Z80B? Not Z80H?

By msd

Paragon (1515)

26-02-2007, 18:34

In some old designs the z80b is used,but it really depends on the batch of z80bs if it can handle the 7.16Mhz. So this is ofcourse not recommended. Don't use the B type

By monant

Resident (48)

26-02-2007, 20:50

my mistake (officially z80b is for 6MHz)

Z80H of course, but this is not the point , all my attention was focused on

questions 1,2,3

By Manuel

Ascended (19468)

27-02-2007, 12:52

Check this for the best Z80H PCB: http://www.hansotten.com/superturbo/supturbo.htm

By AuroraMSX

Paragon (1902)

02-03-2007, 21:49

1) Pin description of Cartridge connectors shows that there are two
reserved line (Pin 5 , Pin 16 What are they for? )

Fill up space between pins 4 / 6, and 15 / 17, respectively ;P
They're not used, NC. Probably reserved for future extensions that never came to be.
2) There is no BUSAK and no BUSREQ , so how can exist two Z80.CPUs at the same time without conflict?Where did you get the idea of having 2 Z80's in one MSX machine? In the 7MHz project the old Z80 is replaced by the new one.
3) Are BUSAK and BUSREQ implemented on some MSX1/2 machine?Probably not. The MSX was not designed for a multi-processor environment.

By monant

Resident (48)

03-03-2007, 00:05

hallo,

Actually,Having 2 processor or a co-processor
was a wish more than a Idea ,

and it ' d have been nice a Z80 plug and play cartridge like FM-Pac for example . (in this PURELY HYPOTHETICAL case no skills wouldn't be required for soldering , replacing..risks of damaging our dear MSX )

but I know the argument is complex...