|
NAMEled —
API for manipulating LED's, lamps and other annunciators
SYNOPSIS#include <dev/led/led.h>
struct cdev *
struct cdev *
void
DESCRIPTIONTheled driver provides generic support for handling
LEDs, lamps and other annunciators.
The hardware driver must supply a function to turn the annunciator on and off and the device name of the annunciator relative to /dev/led/. The priv argument is passed back to this on/off function and can be used however the hardware driver sees fit. The lamp can be controlled by opening and writing ASCII strings to the /dev/led/bla device. In the following, we will use this special notation to indicate the resulting output of the annunciator: State can be set directly, and since the change happens immediately, it is possible to flash the annunciator with very short periods and synchronize it with program events. It should be noted that there is a non-trivial overhead, so this may not be usable for benchmarking or measuring short intervals. Flashing can be set with a given period. The pattern continues endlessly. Three high-level commands are available:
The sequence is repeated after a one second pause. FILES
EXAMPLESA ‘d12 ’ flashes the lamp
*__________*_*______________________________ A ‘ *_*__**_ /usr/bin/morse -l "Soekris rocks" > /dev/led/error SEE ALSOmorse(6)HISTORYTheled driver first appeared in
FreeBSD 5.2.
AUTHORSThis software was written by Poul-Henning Kamp <phk@FreeBSD.org>.This manual page was written by Sergey A. Osokin <osa@FreeBSD.org> and Poul-Henning Kamp <phk@FreeBSD.org>.
Visit the GSP FreeBSD Man Page Interface. |