22 Oct
2011
22 Oct
'11
12:10 p.m.
Not that I know anything about this microcontroller or the game...
Hello Tony
I just found, by reading the interview with the game developer, that the game uses a
custom version of a calculator chip and not directly the PPS-4/1. The PPS-4 seems to be a
more general purpose. About tracing the game doesn't bring much as the game is just a
single chip and a handful of leds. Super super simple circuit.
As an afterthought I think you are right regarding the EAROM.
It must be a masked ROM, so all this doesn't give me many chances.
Sad, coz I really looked forward to recreating the game.
On a side note: I looked in to the data sheets to the PPS-4/1 that John Robertson was kind
enough to dig out of his digital hideout. The PPS-4 was actually a bit more
'sophisticated' than I first thought. One other thing that was unexpected was that
they are powered eg. 0 and negative 9V. I wonder why it's like that...
Regards
Benjamin
I am also the proud owner of a Mattel Battelstar Galatica anno 1979 week =
14.
The chip used in this vintage handheld game is labeled B6001EA and I =
guess it's a Rockwell International PPS-4/1 micro controller (a PPS-4 =
cpu with clock, ram and rom) from sources I found on the net.
I have found very good documentation on the PPS-4 CPU chip (note the =
missing "/1" postfix) here:
http://www.bitsavers.org/pdf/rockwell/PPS-4_Data_Sheet_1974.pdf
Have you traced out enough of the scheamtic of the game to see if this
could possibly be the device in question. Do things like the power pins,
clock oscillator, etc, all match up?
And I found the owners manual for the game here:
=
http://www.handheldmuseum.com/Manuals/Mattel-BattlestarGalacticaManual.pdf=
But I haven't been able to find any documentation on the PPS-4/1 chip =
that I believe is used in the game.
I found that later revisions of the PPS-4 CPU was labeled PPS-4/2 and =
the 'newest' one PPS-4/1 (one would guess that /1 was older than /2).
It might be /2 (chips) and /1 (chip) :-)
I do believe (again from internet sources) that the PPS-4/2 means that a =
minimal system could be made of two chips, a PPS-4/2 and a combined =
RAM/ROM.
So since there is only one chip in my handheld game, I guess it's a =
PPS-4/1 where I again take a wild guess that the above two chip minimal =
combination is in one chip just like most micro controllers today.
I am also guessing that since the chip ends with EA it could have a =
"electrically alterable" rom instead of a maskable rom.
I would be very suprised. EAROM did exist in 1979 (I think) but it was
expensive and small capacity, It would not make sense to use it for the
firmware store of a mcirocontroller, and certainly not in a commerical
product like this.
The ROM _might_ been EPROM, but I doubt that too. Msot likely it is
masked ROM, and there bay be no way to (officially) read it out. There
may be a test mode that allows you to get access to the ROM, whether
that's docuemtned or not I don't know.
-tony