.TH STDD 1 "08 January, 2017" 0.9.8 stdd
.SH NAME
stdd \- a daemon to display the current time on a 7 segment display
.SH SYNOPSIS
.B "stdd" 
[
.B "-d/--daemon"
] [
.B -u/--user
user name ] [
.B -g/--group
group name ]
.B -c/--config
configuration file 
.SH DESCRIPTION
stdd (short for "simple time display daemon") is a handy little daemon for
the Raspberry PI device that can be used to display the current time on a
7 segment display with a HT16K33 backpack from Adafruit Industries. It 
makes heavy use of the python libraries published by Adafruit to control
the display via I2C.

.SH "COMMAND LINE OPTIONS"
.TP 
.B "-d --daemon"
run the program in daemon mode which means, it will detach from the shell and run in background 
.TP
.BI "-u --user " "user name"
instructs stdd to drop privileges and run with the privileges of the defined user. Please note that stdd nees to be started as root for this to work and the user (or his primary group) needs to be able to access the i2c device.
.TP
.BI "-g --group " "group name"
instructs stdd to drop privileges and run with the privileges defined user. Please note that stdd nees to be started as root for this to work and the group needs to be able to access the i2c device.
.TP
.BI "-c --config " "configuration file"
define the path to your stdd configuration file. This is usually needed to start the program in both modes.
.TP
.BI "--version"
print version information and exit.
.SH EXAMPLES
.TP
.B stdd -c /etc/stdd.json
minimal example using the default configuration file
.TP
.B stdd -c /etc/stdd.json -u i2cuser -g i2c -d
start with the privileges of user i2cuser, group i2c and run as daemon
.SH CONFIGURATION
The configuration file is in json format and usually found in /etc/stdd.json. The following options can and should be set in the configuration file:
.P
hw_address:	hardware address for your display, a common value is "0x70" use i2cdetect to find yours if it doesn't match
.P
blink_colon:	define if you want the middle colon to blink, false = off, true = on
.P
brightness_high:	value used for "high" brightness, valid values are 0-15
.P
brightness_low:	value used for "low" brightness, valid values are 0-15
.P
set_brightness_low:	time of the day to change the brightness from high to low
.P
set_brightness_high:	time of the day to change the brightness from low to high
.P
syslog_level:	maximum syslog level to log, stdd uses debug, info and error
.P
syslog_facility:	syslog facility to use for logging (default: user, can also be daemon)
.SH FILES
.TP
.B /etc/stdd.json
the default path to the configuration file
.SH "SEE ALSO"
.TP 
.B http://learn.adafruit.com/matrix-7-segment-led-backpack-with-the-raspberry-pi
Adafruit tutorial for attaching a display to the Raspberry PI and using the library
.TP 
.B https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code Adafruit
sample code used in this project
.SH AUTHOR
Helmut Pozimski
.SH COPYRIGHT
2013-2016,  Helmut  Pozimski, 3-Clause BSD license