Re: A83: TI serial port protocol

To: assembly-83@lists.ticalc.org
Subject: Re: A83: TI serial port protocol
From: goflo@pacbell.net
Date: Tue, 27 Oct 1998 12:47:32 -0800
Delivered-To: assembly-83-outgoing@towerguard.unix.edu.sollentuna.se
References: <3635EA43.488FDB91@wam.umd.edu>
Reply-To: assembly-83@lists.ticalc.org

Hi Amy

The port has three wires, red, white, and ground. Red & White are
signal, normally high, active low. Red = 0, White = 1.
Bytes are sent least significant bit first.
Bit protocol is as follows:

TX pulls Red/White to ground for bit = 0/1
RX pulls inactive (high) line to ground
TX releases its line, waits for RX to release other line
Next bit

As you can see, this is quite different from most serial protocols.
Interfacing an ADC to the 83 can be done with a PIC, or similar
processor. Also, if 8-bit resolution is good enough some PIC's have
on-board ADCs...

Hope this helps.

Jack

ALoomis wrote:
> 
> Can you tell me anything about it?  I'm trying to send a signal from an
> analog to digital chip to a TI-83 and TI's page says they have a routine
> that will recieve a byte of data in "TI-83 protocol" so my problem seems
> to be getting the signal into that protocol.  Unfortunately they don't
> tell anything more about it.  If you have any ideas please respond.  If
> not I'm sorry to waste your time.
> Amy Loomis

References:

A83: TI serial port protocol

From: ALoomis <aloomis@wam.umd.edu>