Looks like 2 banks for the software, one for the system and one for 8201
emulation.
m
- Original Message -
From: "Stephen Adolph"
To: "Model 100 Discussion"
Sent: Friday, February 17, 2017 8:13 PM
Subject: Re: [M100] Parts for an NEC PC-8300
> oh that's very interesting. ok. I wond
Looks like it might be the same idea as 64Kb ROMs vs. EPROMS; most of the ROMs
used in arcade machines, lots of Commodore models and even the IBM PC were 24
pins whereas the 'normal' 64Kb EPROMs were 28 pins with the exception of one
Motorola part; a simple adapter took care of the problem.
Any
Looks that way; what confused me was that there are images out there (even with
the Y2K adjustment) that are labelled 27C512.
m
- Original Message -
From: "Stephen Adolph"
To: "Model 100 Discussion"
Sent: Friday, February 17, 2017 8:26 PM
Subject: Re: [M100] Parts for an NEC PC-8300
I should have done a bit more digging. NEC makes two masked roms. And probably
more likely that they used one of their own chips since they did the design
tweaks on the 8201 to make the 8300.
uPD23C1000
uPD23C1010
I'm not sure that helps someone who doesn't have an original system rom for
their
The only masked ROM I have found that is 128k and 28pins is:
(1M) 128k x 8 mask rom (TC531000)
A15 1 +-v-+ 28 Vdd
A12 2 | | 27 A14
A7 3 | | 26 A13
A6 4 | | 25 A8
A5 5 | | 24 A9
A4 6 | | 23 A11
A3 7 | | 22 A16
A2 8 | | 21 A10
A1 9 | | 20 CE/
A0 10 | | 19
On Fri, Feb 17, 2017 at 5:14 PM Stephen Adolph wrote:
> oh that's very interesting. ok. I wonder what the pin assignment is.
>
> what does the 8300 need 96k of rom for 8300 mode for, vs only 32k rom for
> 8201?
>
Well there's an xmodem implementation in there.
-- John.
VT simulates it with 4 rom banks.
so, .. it must be 128kB.
I just have no idea what the pin assignment on a 28 pin socket could be.
..Steve
On Fri, Feb 17, 2017 at 8:20 PM, Stephen Adolph wrote:
> ROM0 is 28 pins. I went downstairs to open it up again and count...
> can't be 27c1001. that's 32
ROM0 is 28 pins. I went downstairs to open it up again and count...
can't be 27c1001. that's 32 pins as you say Mike.
so, still a mystery.
I thought maybe it could just be a 64k ROM - that clearly can fit in a
28pin socket.
Steve
On Fri, Feb 17, 2017 at 8:13 PM, Stephen Adolph wrote:
> oh tha
oh that's very interesting. ok. I wonder what the pin assignment is.
what does the 8300 need 96k of rom for 8300 mode for, vs only 32k rom for 8201?
a schematic would be golden. All I can say is there is no other ROM
on the board.
Steve
On Fri, Feb 17, 2017 at 6:51 PM, Kurt McCullum wrote:
>
Ah, OK; we know that there are four 32KB ROM pages (plus one 32KB Option ROM
slot); if the ROM0 socket is 32 pins then that (plus Kurt's reference) would
suggest that everything is in one 27C1001 EPROM (with presumably a second 28
pin socket for the Option ROM.)
Unfortunately at this time I don
I don't have an 8300 here but web8201.net has some detailed technical docs.
Here is a page describing the PROM as 128k
http://web8201.net/NEC8201emulation.asp
Kurt
-Original Message-
From: M100 [mailto:m100-boun...@lists.bitchin100.com] On Behalf Of Stephen
Adolph
Sent: Friday, Februar
from my perspective-
* there is a single socket ROM0 for the main ROM
* ROM1 is for option roms.
* there is no other ROM in the unit.
* it is a 32pin socket, and so it must be no larger than a 64kB rom.
Not likely to be 32kB.
* i'd bet that OUT163,2 sets A15 on the socket.
* no idea what the pinou
Mike
There are places for two ROMS. In the regular PC-8300 there is only one
ROM used for Basic.
83100 - 438
N83A Basic
1986
Microsoft
8649 - Z69
In the other unit, which no longer has it's regular ROM, there are two ROMs
D276256D-20
D276256G-25
I hope this helps.
Looks like it's up to you, Fred:
Can you open up the 8300 and tell us exactly how many and what kind of ROMs or
EPROMs are in there, i.e. any labels and/or part numbers?
Since at least one is custom firmware it's probably in an EPROM (as opposed to
a ROM) and will probably have a standard numbe
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