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David Schleef 2001-07-10 22:55:32 +00:00
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demo/ledclock.c
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/*
* Digital I/O example
* LED Clock demo
* Part of Comedilib
*
* Copyright (c) 1999,2000 David A. Schleef <ds@schleef.org>
* Copyright (c) 2001 David A. Schleef <ds@schleef.org>
*
* This file may be freely modified, distributed, and combined with
* other software, as long as proper attribution is given in the
* source code.
*/
/*
* Requirements: A board with a digital I/O subdevice. Not just
* a 'digital input' or 'digital output' subdevice, but one in
* which the channels can be configured between input and output.
* Requirements:
* - A board with a digital output subdevice and a subdevice that
* can trigger on an external digital line. A parallel port
* satisfies these requirements.
* - A Fantazein LED Clock modified so that the individual LEDs
* can be controlled directly by the digital I/O lines.
*
* The Fantazein clock has 8 LEDs arranged in a row on a wand that
* sweeps back and forth at about 15 Hz. Unmodified, the firmware
* of the clock lights the LEDs at the appropriate time to print
* words and the time of day. Since the wand moves quickly, it is
* barely visible, so it looks like the image floats in the air.
* Stuart Hughes modified a clock so that the LEDs could be controlled
* directly by the parallel port of a computer, and wrote the
* appropriate software using RTAI to create a stable image. This
* is an attempt to port the demo to Comedi.
*
* It needs much work.
*/
#define _GNU_SOURCE