Re: TI-H: Re: Ir Link compatability
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Re: TI-H: Re: Ir Link compatability
Gregory Whitmore wrote:
> I have only tested it with the TI-92, it works fine with no added
> software. I have done nothing with the expander SF. I have not done
> testing with any games.
Sorry to say this, but I refuse to believe that your IR link actually
works. None of the parts does any TI protocol-to-RS232 and vice-versa
conversion, and the send and receive modules are too simple to send the
states of both link port pins in both directions, so there is no way
information could be transmitted over the link! Also, what the $4 serial
link does is that it converts the TTL voltage levels of the link port to
RS232 voltage levels, and MAX223 does the same procedure backwards, so the
result is again TTL. In effect, the whole circuit seems to work so that one
of the link port pins is connected "directly" (with a stupid voltage
conversion in between) to the Tx module and the other link port pin
similarly to the Rx module. This is not enough to send any data over the
link with the TI protocol. It would work with the RS232 protocol, but the
TI doesn't use it. The only way to make your IR link work is to use Graph
Links instead of the $4 serial links.
Have you only tested with Graph Links? Have you ever successfully sent e.g.
a string of data over the link, or only tested that it can send and receive
voltage states?
As of now, I believe that either your IR link is a hoax or that you don't
know enough electronics to build one that works and test it adequately.
-Ozone, a skeptic
--
*** Osma Suominen *** ozone@clinet.fi *** http://www.clinet.fi/~ozone ***
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