TiLP
a TI Linking Program
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This project aims to develop a multi-platform linking program
for use with all TI graphing calculators (TI73 ... V200PLT).
The GUI has been written with GTK+ (the Gimp ToolKit).
HISTORYwhy it all started ?
I have had Linux installed at home since
1997 and I am working more and more with Linux. During my 3 years in
preparatory
classes, I have made some TI92 <-> PC link cables and provided a
program
to use them (WinLink92 for Windows 95) for my friends who have TI92s as
well as myself. Unfortunately, I couldn't find a similar program for
Linux
that would work with my TI92 link cable and as far as I could tell from
ticalc.org,
the need existed.
A first solution was WINE (i.e. run WinLink92 under WINE). This works but this did not constitute an efficient solution. As I am fond of electronics (digital electronics and micro-processors/controllers) and computer science (Pascal and C/C++ programming), I decided to write one. All that remained was to find the protocol (hardware and software specifications) providing the communication between the TI calculator and the PC. Fortunately, a friend had got these specs. Unfortunately, these were incomplete and did not cover the hardware protocol. Thanks to some electronics, I managed to complete these specs.
how?
My father was lucky enough to have an oscilloscope which allowed me to get a general idea of the signals. The problem is that an oscilloscope does not have any memory and so cannot store a history of the signals. So, I got to work and built a sort of 2 channel oscilloscope with memory (actually a logic analyser) which allowed me to start sampling at any time and record them to look at later. The first version was based on an Intel 8032 microcontroller running at 12MHz (1 million instructions per second) and was not fast enough to track the signal.
So, I chose another way: a DSP (Digital Signal Processor) starter kit based on a Texas Instruments TMS320C31 running at 50MHz (25 million instructions per second), equipped with 8Kb of embedded RAM to record the samples. I also quite like the idea of working out the Texas Instrument's protocol with a Texas Instruments card!
The first version allowed
me to
get
some chronograms, but these still needed decoding. A friend (whom I
thank)
has suceeded in decoding them while I was installing Linux on his
brother's
PC. The hardware protocol was now decoded and now I could develop a
second
version which allows me to directly get the bytes exchanged between the
PC and the TI.