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ece4894 design project Introduction
This design project started as a generally simple concept: convert a serial
signal to infrared and demo a serial device working across IR on a Compaq IPAQ.
The tools we planned to use were an Altera FLEX10K20 PLD, any discrete components
necessary on the serial device end, and the IR port on the Compaq IPAQ. However,
it was realized that the IR port on the Compaq was too difficult to interface with,
and it was better to work with a PS/2 mouse because the Altera PLD board contained
a built-in PS/2 port.PS/2 to IR Hardware
Because the PS/2 mouse operated on a seperate clock which we could not control,
the mouse required many bytes sent to it in serial to send data properly, and
we did not have the necessary hardware to recieve on both ends, a seperate VHDL
module was required to interface explicitly with the mouse and provide data lines.
This module was furnished for us by Dr. Hamblen. Another module was necessary to
detect when the state changed and to handshake with the IR transmitting module.
The IR transmitter component generated a series of serial bytes with special framing
and modulated the output with a 40kHz modulator to be received on the other end.
Another VHDL component generated a 40kHz clock and a baud rate clock (1200 baud used).
This signal was then driven to an IR LED and was ready for reception.IR to Serial and Software
The IR signal was demodulated at 40kHz with a Radio Shack detector module. It was
then fed to an MAX232A chip to generate the necessary voltages for serial connection.
The IPAQ's built-in serial-port (special cable required) was used, and a simple
application was written to keep track of the mouse data.
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