TI-H: Re: Hey I don't know.

To: connect-85@lists.ticalc.org, ti-hardware@lists.ticalc.org
Subject: TI-H: Re: Hey I don't know.
From: Leif Gregory <ldgregory@biogate.com>
Date: Sat, 04 Oct 1997 23:54:01 +0900
Reply-To: ti-hardware@lists.ticalc.org

At 07:32 AM 10/4/97 -0500, you wrote:
>
>I'm fooling around with one of the FM tuners now and have looked at the
>parts, recorded them and now will try to build a smaller FM tuner.  I really
>don't know if I have anything, other than to open one yourself.  My next step
>is to build one smaller.  I have also looked at a simple Wakie Talkie send
>receive.  The one I took apart was old and didn't go more than 20 feet.  I
>still don't know how someone could send recieve at the same time without
>freezing the Calc.  Sure you could alternate like chat programs for the 85
>but that would be slow.  Maybe that is what we need first.  I'll get place
>with any more 'to some 'stupid' and outdated info.
>
:x--------------------  SNIP  -------------------x:

About the alternating. Well, I think the best thing would be to have a
master, and all other calcs are assigned a number as slaves.. i.e.

master = 0
slave1 = 1
slave2 = 2
slave3 = 3

etc...

When you run a program that is going to use the FM link, it asks on each
calc who they are. 0,1,2,3 etc.. If all the hardware does is send when it's
told to and receives at all other times. This would involve shutting the RX
off on the Transmitting calc, as it would receive it's own signal.  I think
it would work. The biggest thing I think is error correction.. FM is a
pretty busy band, hence noisy, and FM is pretty good at penetrating walls.
You could even make timing and protocol control (N81, E71 type stuff)
software too. I don't know how much RAM that would take, so some may have
to be built hardware. Do the async thing. 1 start bit, 8 bit data, 1 stop.
BTW, I'm posting this to the listserve. Talk at you later...

Leif

- ldgregory@biogate.com
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