[TI-H] PIXpander & Stuff

To: ti-hardware@lists.ticalc.org
Subject: [TI-H] PIXpander & Stuff
From: Krevinek <krevinek@mac.com>
Date: Tue, 23 Apr 2002 15:32:33 -0700
Reply-To: ti-hardware@lists.ticalc.org


Well, this is a rather late post compared to others who have made an 
attempt, but I have gotten fairly close to getting a heavily modified 
PIXpand design working properly. Unfortunately, it seems to be rather 
sensitive to battery levels, especially when communicating data to the 
TI. My last 9V just 'died' because its voltage kept dropping to 4.5V or 
less anytime the TI pulled one of the lines to ground, maybe I need a 
resistor there (I use 2 pins for the connection, with 18k pullup 
resistors).

Also, I am looking into a proper solution for those using cards that 
require 7.2V like that ultra-mega-super-duper 96 page card that can hold 
a good 10+MB of data across those pages. Right now I am preferring a 
route that involves a 7.2V regulator and creating a tap line of 
resistors from 7.2V to Ground to power the PIC and the 3.6V line to the 
card. If someone has a better method to get 7.2V, 5V and 3.6V in the 
same circuit, tell me, as the tap method drains quite a bit of 
electricity, and the regulator is bad enough.

I can talk to my TI-86 just fine while running of a AC->9V DC converter 
right now, and the PSX card I use for testing is still a little flakey, 
but I think I have a working PSX communication method within my grasp. 
(Talking at the full 250Khz too, which Sami's version doesn't do)

Follow-Ups:

[TI-H] Re: PIXpander & Stuff

From: RanDom_ErrOr <bond1298m12_sod@yahoo.com>