I'm not at all sure what you've said here, Allison. Aren't we in agreement?
The 2101 was a 1k-bit sram organized as 256x4 with separate inputs and
outputs.
The 2102 was a 1k-bit sram organized as 1kx1 with separate in and out.
The 2112 was a 1 k-bit sram organized as 256x4 with common ins and outs.
They're all different, but whoever wrote the message to which I attached
mine already knew that it was a 256x4 in a 22 pin package 0.400" wide.
Additionally, there was a 2115 which was a high-speed (25 ns) 1kx1 sram with
open drain outputs. I saw few applications for that one, however. It had a
cousin, the 2125, which had the same pinout and architecture, but had
tristate outputs.
Things got muddled when the iNTEL folks started using unused numbers in the
1K-bit family, e.g. 2114, for memories larger than 1k-bits. The 2114,
however, was just a microcomputer-compatible (slow) version of the already
widely used 2148/49, which was a fast (35-70ns) equivalent to the 2114.
They also made the 2147 which had the same bit count as the 2148/49 but with
a 4kx1 organization with separate input and output and pinout compatible
with the much slower TMS4044.
The PET 2001 was pretty early among the production microcomputers, hence may
have come along too early to capitalize on the high-volume production of the
4K-bit srams.
Dick
-----Original Message-----
From: allisonp_at_world.std.com <allisonp_at_world.std.com>
To: classiccmp_at_classiccmp.org <classiccmp_at_classiccmp.org>
Date: Tuesday, March 21, 2000 10:40 AM
Subject: Re: Mos Technology RAM wanted
>
>2101 was 1kbits but by 4. 256x4 22pins.
>
>For that time it may have been 2112 or other cousins.
>
>Allison
>
>On Tue, 21 Mar 2000, Richard Erlacher wrote:
>
>> I think the basic number you're looking for is "2101" from the same 1K
>> series as the famous "2102" which is a 16-pin 1kx1 with separate in and
out.
>> The 2101's I have are not fast enough to meet the 200ns spec. However,
not
>> much of anything that was readily available at the time the PET model
2001
>> came out was that fast. Either it was quite a bit faster, e.g. 2147,
2115,
>> etc, or it was slower, e.g. 2114, 21L02, TMS4044 etc, which were
typically
>> 450 ns at that point in time. Those 450 ns parts worked handsomely with
the
>> 1 MHz 6502. Perhaps you'd be able to use a 2101.
>>
>> Let me know if you think that might work for you. I've had my small
supply
>> (maybe 4 pieces) since back in '76-'77 when I got my original 6501,
though
>> I've never used them for anything.
>>
>> Dick
>> -----Original Message-----
>> From: Pete Turnbull <pete_at_dunnington.u-net.com>
>> To: classiccmp_at_classiccmp.org <classiccmp_at_classiccmp.org>
>> Date: Tuesday, March 21, 2000 2:39 AM
>> Subject: Re: Mos Technology RAM wanted
>>
>>
>> >On Mar 20, 13:23, John Honniball wrote:
>> >>
>> >> On Sun, 19 Mar 2000 21:28:09 GMT Pete Turnbull
>> ><pete_at_dunnington.u-net.com> wrote:
>> >
>> >> > One of the MCS6550 RAMs has gone west. Does anyone have a spare, or
an
>> >> > equivalent, for sale? It's a 22-pin 1024 x 4 200ns static RAM.
>> >>
>> >> I'll have to check the RAMs in the spare PET that I
>> >> keep in the garage. Can't remember whether they're SRAMs
>> >> or DRAMs in the bigger PETs.
>> >
>> >Only the oldest 2001-x PETs use those SRAMs. I guess it's time to build
>> >that upgrade board (a PAL, a pair of EPROMS, and some 6264s, a 62256, or
>> >some cast-off PC cache).
>> >
>> >--
>> >
>> >Pete Peter Turnbull
>> > Dept. of Computer Science
>> > University of York
>>
>
Received on Tue Mar 21 2000 - 12:02:08 GMT