Re: [stella] PCB Pinout

Subject: Re: [stella] PCB Pinout
From: "Chris Larkin" <clarkin@xxxxxxxxxxxxx>
Date: Sun, 17 Nov 2002 23:36:15 -0800
Man! This is frustrating... If I could just find the 2532 datasheet.

If the 2532 is different from the 2732 in that is does not have an /OE line
for some reason reads are handled from the /CE line, and what should be the
/OE line is only the Vpp line, then I can understand how the PCB works.

>From this site, that appears to be true, there is no /OE or /G line... only
Vpp.
http://www.xs4all.nl/~ganswijk/chipdir/pinusr/2532.txt

Vpp is the pin that you supply the uber amounts of voltage to, to burn the
EPROM.  If the pin was only VPP then you can just tie it to Vcc and be done,
however in the case of the 2732 the Vpp pin is also the /OE or /G pin.

Has anyone made a 2732 cartridge? How did you wire it?

You can't wire the /OE pin to the Vcc and expect the chip to work... there
must be an answer.  /OE has to be dropped, after the address is written to
the chip.  So the cartridge has to somehow write the address and then drop
the /OE line in order for a 2732 EPROM to work. Is this what the 2600 does
with the A12 line? Which is why we have to invert it?  If that is the case,
all I should have to do is wire the inverted cartridge line to the /OE pin
as well as the /CE pin on the 2732 and it should work fine...

--Chris

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