Philip wrote:
>>>Ah, the famous /20-series... Can anybody tell me the difference
between
>>the
>>>VG8235 and the VG8235/20???
>
>
>Well, as far as I know, there is just a little difference between
these two
>machines. I used to have the 00-version and that caused many
problems!!
>
>Why, coz the 00 has a hardware memory bug, which makes it IMPOSSIBLE
to
play
>most cracked MEGAroms on disk, although you HAVE the necessary 128kB
of
>memory. In the 20-versions, the bug is solved, so with that machine,
you
CAN
>play the cracked games...
>
>Greetz,
>
Does this problem have something to do with the read of the mapper
registers ?
I know that some of the japanese memory mappers has no possibility to
reply the data on the
mapper registers , making it unreadable. (You get only FF from it when
reading)
Wich makes allmost all dutch software unusable on it. I was working on
my own memory mapper
project using static memory chips.
I used 8 62256 , 2 74ls138 , 1 74ls30 and 2 74ls670
The 1st 74ls670 does the mapper mapping and the second holds the
register value to make the
mapper ports readable. Without this second one I noticed that programs
like Moonblaster
or any other european software wich uses mapper hangs or resets the
coputer while loading.
By adding the 2nd 74ls670 I got all the tested software running fine
....
I´m going to put the schematics online when I finish all my MSX
hardware projects .....
--
Leonard Silva de Oliveira MSX user since 1987
MSX users channel on the undernet : #MSX the MSX user's channel
Nickname : Vic_Viper
[EMAIL PROTECTED]
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