[TI-H] Re: I remember hearing of a ti hub project a few years ago...
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[TI-H] Re: I remember hearing of a ti hub project a few years ago...
Strictly speaking, a hub would merely amplify the signals and retransmit
to ALL connected devices. Even for a broadcast (one calc sends to
multiple), this would not be compatible with the built-in link protocol.
(which needs bidirectional communications no matter what)
A simple way to make a hub/router work with basic programs is to have a
connect packet set to it with an asm program to set up where everything
goes until another connect packet is recieved. This does require the
device to track packet start&ends, but that shouldn't be too much of a
problem. ((If done properly, this might even let you connect multiple
hub thingies together for a larger netwoek.)
The data buffer with a pic16f84 is essentially zilch. You can't hope to
buffer entire packets except perhaps VERY small ones. There probably is
enough ram to track packet start&ends, so it's likely not a bad
microcontroller to use (if you can get one ;)
An interesting thing with this chip: I have had a circuit work with no
power, just connected to one ti-86 on two io lines. It even had enough
power to drive an led display.
-josh
On Sun, 29 Apr 2001 09:55:15 -0700 (PDT) Adam Thayer
<krevinek@matrix-z.net> writes:
>
> Here is another idea:
>
> Get someone to learn how to program a PIC Microcontroller and use it
> to setup a basic 4-Port Hub which will send data to each calc if
> data is sent to it. Of course this particular setup will not be
> TI-OS compliant to an extent. You could send vars to multiple calcs,
> but using TI-Basic for data transfer is out, unless drivers add a
> couple BASIC functions for hub use.
>
> All one would have to do is wire a set of submini jacks into the B
> array on the Microcontroller and have some power supply to make sure
> the PIC gets 5V and a clock. One with minor skills in the PIC would
> be able to hack up a basic schematic in about an hour, and if we
> could get the IR-link code, could use that to code up the
> Variable-transfer code. The only drawback is that the data buffer is
> VERY small, a measly 16k or less, so transfer conditions have to be
> just right, unless some sort of Static RAM chip of something is also
> used off-chip. The device wouldn't be difficult, but since I cannot
> seem to get any PIC to program (especially the F84), I am kinda
> stuck on development myself.
>
>
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