Kasten.PETG%his-billerica-multics@BRL.ARPA (11/28/83)
From: Phil Kasten <Kasten.PETG%his-billerica-multics@BRL.ARPA>
I placed the following transactions on a forum meeting and received no
replies. Perhaps someone here can help me...
[0180] Kasten.PETG 11/11/83 1336.6 est Fri Bulletin_Board
Subject: Colecovision...
I was just wondering if anybody knew the following info: 1) What is the
pin-out of the cartridges? What are the signals? Do they (Coleco) supply
this info upon request? (I assume not).
2) What is the memory chip used in the cartridges?
3) What is the pinout of the expansion bus--is it identical to the Z-80
pinout?
Answers to these questions and any other technical info anyone may know
would be apprecialted.
You can mail replies to: Kasten.PETG%bco -at HI-MULTICS if you wish,
or just put the info here.
Thanks in advance...
Phil Kasten
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[0183] Kasten.PETG 11/12/83 1950.7 est Sat Bulletin_Board
Subject: Re: Colecovision...
Upon "looking into the matter" (or more appropriately, looking under the hood)
one finds two chips. One is a Texas Instruments chip, the TMS4764.
Is this a 2764 look-a-like? Also, there is another chip which reads,:
copywrite 1982 Coleco
Industries Inc.
IM7364CPG
R73204A 8301
Is this just another ROM? Any clues?
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[0184] Kasten.PETG 11/14/83 1332.6 est Mon Bulletin_Board
Subject: Re: Colecovision...
Looking even further into the matter reveals: TMS4764 is an 8K x 8 ROM. It
has 24 pins divided as: 13 address pins, 8 data pins, 1 VCC pin, 1 ground
pin, and one chip control pin. My question is now this:
"Pin 20 can be programmed during mask fabrication to be active with either a
high- or a low-level input. When the signal is active, all eight outputs are
enabled and the eight-bit addressed word can be read. When the signal is not
active, all eight outputs are in a high-impedance state...A mask programmable
option is to utilize pin 20 in a power-down mode. In this mode, pin 20 is
clocked. When it is high, the chip is put into a standby mode. This reduces
ICC1, which in the active state is 80mA maximum, to a stanby ICC2 of 20mA."
Does anyone out there know which way Coleco has their ROMs fabricated? (i.e.
how is pin 20 used?)
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[0185] Kasten.PETG 11/14/83 1336.0 est Mon Bulletin_Board
Subject: Re: Colecovision...
I apparantly forgot to give reference to the paragraph I quoted. It was from
the Texas Instruments MOS Memory Data Book, 1982, (page 181).
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Finally, will 8K x 8 EPROMS require too much power (the T.I. ROMS use
about 50% less power than EPROMS) and will they be too slow? What is
the closest EPROM to the T.I. ROMS?
All and any information will be appreciated. Thanks in advance,
Phil Kasten