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..

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.

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 ?

2) Because there actually can't.

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

Quote:

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.

Z80B? Not Z80H?

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

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

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

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

Quote:

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.

Quote:

3) Are BUSAK and BUSREQ implemented on some MSX1/2 machine?

Probably not. The MSX was not designed for a multi-processor environment.

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...