Author
| 2+ in a NMS 8245?
|
OeiOeiVogeltje
msx addict
Posts: 353 |  Posted: November 29 2008, 13:56 |
i recently aquired a Yamaha V9958 Chipset
and now i want to put it in a NMS 8245
and of course no shematic is to be found!
so my question;
Does anyone have any stuff lying around on 8245 expansion (of any kind)?
thanks!!
|
|
Erikie
msx addict
Posts: 320 | Posted: November 29 2008, 21:54 |
|
|
Jipe
msx addict
Posts: 408 | Posted: November 29 2008, 22:09 |
is possible
i make a 8235 with a 2+ VDP but i change EPROM and added another EPROM for all function 2+
eprom change with keyboard AZERTY or QWERTY
i have not the schematic for 8235 but i can make it
|
|
OeiOeiVogeltje
msx addict
Posts: 353 | Posted: November 29 2008, 22:40 |
Erikie
thanks for that link
im affraid lines like this one; "make a connection with p26 of the VDP and the resistance R1 inserts you a diode"
makes me wanna use etreme caution actually doing this
in other words
i dont understand what he means
|
|
Jipe
msx addict
Posts: 408 | Posted: November 29 2008, 23:41 |
for the 2+ VDP required this schema
pin 26 VDP ------i<i------- pin 24 Z80 (Wait )
diode is 1n914 or 1n4148 type
|
|
OeiOeiVogeltje
msx addict
Posts: 353 | Posted: November 29 2008, 23:45 |
how do you know that?
|
|
RetroTechie
msx freak
Posts: 224 | Posted: November 30 2008, 02:01 |
Bullshit alert: 
* In the page linked above, I spotted 3 errors already, without even needing some databook to spot those.
* If you do grab those databooks, read that page again and *can't* spot several errors, then you shouldn't even try this mod. More exactly: as described in above page, you shouldn't try at all - won't give you an MSX2+, may damage your V9958 |
|
manuel
msx legend
Posts: 4321 | Posted: November 30 2008, 13:14 |
RetroTechie: OK, please make a good description then and post it here  |
|
Jipe
msx addict
Posts: 408 | Posted: November 30 2008, 14:30 |
i know by a old schema for upgrade msx2
in the data book of msx2+ wait signal from VDP is direct to wait signal from Z80
i have a 8235 and a 8280 with VDP V9958 inside and work fine
fore more info see this link
http://msx.retro8bits.com/msxdocs/msx2plus.pdf |
|
OeiOeiVogeltje
msx addict
Posts: 353 | Posted: December 03 2008, 19:43 |
well
this is confusing.......
|
|
Erikie
msx addict
Posts: 320 | Posted: December 03 2008, 20:34 |
Isn't it possible to do the same connections as in a 8250? I have not yet looked at my 8245 but I can try to put a 9958 in it. Still have one at hand along with a socket |
|
msd
msx professional
Posts: 695 | Posted: December 03 2008, 21:40 |
"Er wordt gesuggereerd dat er een diode van pen 26 (V9958) aan de #wait-lijn van de Z80 gemonteerd moet worden. Echter blijkt dit in de praktijk niet nodig te zijn. Tot zo ver wat betreft de ombouw naar een V9958 in een NMS 8250/55."
It think this is wrong. It is needed.. However only used when you enable it in the vdp iirc
|
|
|
|
|
