Re: Modem??!?
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>Has anyone out there (besides me) given any thought to building adapters
>to make the TI (mines an 85) more and more like a portable computer? When
>I get the ASM program for the 85 (if there is one) I am going to convert a
>2400 hayes-compatible for use with it. I am also working on an infrared
>link for ti's, so you don't jack together. I need this for school...
I have. I tried to build a parallel interface to my TI-85 to connect a
printer to it. It almost worked (just the hanshaking was a bit buggy, but I
think I've fixed it but not tried it - lost my cable and now my TI is broken
:( ). It was meant to be a bidirectional 8-bit port which would be
Centronics compatible. Later I was going to build a serial port, too, but
then I heard of the I2C bus and stopped making up my own messy electronics
for my TI - everything should be much easier with I2C. Too bad I've lost my
interest already, at least for this summer.
But a TI-85 connected to a modem, even a slow one, would be really nice to
have. Maybe you could even connect the RS-232C interface of the modem
directly to the TI link port, with just a MAX232 voltage converter in
between. One of the wires of the link port would be used for sending data
and the other for receiving it. You would, though, have to use
XON/XOFF-handshaking or none at all, because there would be no spare wires
left for RTS/CTS or DTR/DSR hanshaking.
Another option is to use the link port as an I2C bus and connect some
microcontroller to it, and the microcontroller could then work as a
I2C-RS232C converter, again with a MAX232. Or the microcontroller could be
connected to a UART chip. Using the I2C bus would probably require more
components, but it should be more straightforward to build, could have some
buffering to ensure no data is lost and would be more standard. I haven't
found any information on UART chips that connect to the I2C bus, but maybe
some exist.
An IR link would maybe be possible to build, but it would require two
wavelength bands for the two wires in the TI link port. I don't know if
that's possible.
-Ozone
*** Osma Suominen *** <a href="mailto:ozone@clinet.fi">ozone@clinet.fi</a> *** http://www.clinet.fi/~ozone ***
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