TI-H: Memory expansion: ESF

To: ti-hardware@lists.ticalc.org
Subject: TI-H: Memory expansion: ESF
From: "Richard Piotter" <richfiles1@hotmail.com>
Date: Sat, 07 Mar 1998 10:37:25 PST
Reply-To: ti-hardware@lists.ticalc.org

>Last I checked (a week ago) there were still about 2000 each of the
>NM29A040 and NM29A080 chips available for purchase. These are the 512kB
>and 1MB chips which were used at the core of the Expander SF by Mel 
Tsai.
>
>If I wrote an enhanced TI-85 driver for the ESF, got some of these 
chips,
>and built them into expanders, how many people would buy? Cost for a 
512kB
>ESF would be about $25 to $33, and the 1MB ESF would around $40.
>
>And how many people would pay more for an expander, based on the same
>chip, with microcontroller to run an LCD panel and a few buttons in a
>small alpha-numeric pager case? This particular model could be 
controlled
>entirely through TI-OS, but I'd make an ASM driver as well.

I would recomend building the ESF as a SPinTerface cartridge. The ESF 
was so small that you could buy one of those 9-pin connector housings 
(from Radio Shack. Not the actual connecter, but the plastic case around 
it). The ESF chip would fit nicely inside of it and still have room to 
spare!!!

The link version of the ESF could be continued, but cut standard TI-TI 
link cables. A lot of people complained about the mouser cables actualy 
damaging the link port! I had to fix one once!

I'd say, if you do go with a microcontroler, make it use the AT whatever 
chip in the EII. If you make some awesome microcontroler based system, 
use a decent part. DO NOT use the ESF chip for ANY new designs or when 
they do finaly run out, you'll be caught in a MEGA jam. Use the same 
chip as the EII and them MMODs can be exchanged!!! Give it a cool name 
like E2 (E squared). It'd look cool on a web page, and does make it look 
interesting. If you can figure out TI link protocol, and emulate it, you 
could use the lCD to send stuff and the link window to send stuff. It 
could possibly even recieve from the TI graphlink software!!!

Try it, but DO NOT USE THE OLD ESF CHIP FOR ANY NEW DESIGNS. This will 
only lead to it becoming obsolete again.

I do however recomend making the SPinTerface ESF, because of it's low 
price and small size!!!

Richard Piotter
richfiles1@hotmail.com

The Richfiles TI Page
http://www.geocities.com/SiliconValley/Lakes/5081/Richfiles.html


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