User manual

 2011 Microchip Technology Inc. DS41581A-page 21
Under clock standard, the user has the option to toggle between [24-hour] and
[12-hour] time. If [12-hour] is selected, it should reflect an accurate representation of
[24-hour] time using an ‘A’ or ‘P’ display to indicated morning or evening time.
By choosing Set Alarm, the user will have the option to choose a 30 or 60 minute nap
timer or to set a custom alarm time. If the user chooses Custom, a display similar to Set
Time will be displayed, giving the user the option to increment hours and minutes to a
desired alarm time.
The user has the option to choose to enable/disable the alarm by selecting Alarm.
If the user selects Wake-Up, it will toggle between multiple options. The wake-up fea-
ture is only used in Conserve mode. Its function is to wake the device from Sleep at the
specified time periods (Wake-Up) to go into Active mode for a short period of time (Dis-
play Length), and then return back to Sleep until the set amount of time elapses again.
The user has the option to select to wake-up every 15, 30 or 60 seconds; or the user
can choose to not wake-up and display the active window. If the user chooses the
option None for the wake-up timer, the Display Length value will be equal to 0 and will
not display for any amount of time. The Display Length feature is only used in Conserve
mode. Its function is to display the active display for a set amount of time of 1, 5 or 10
seconds after waking the device from Sleep.
2.2.2.2 FREQUENCY SETTINGS
Under the frequency settings the user will have the option to choose between four sys-
tem frequency’s which range over multiple power usage ranges. The user can choose
to run the system at: 32 kHz LFINTOSC, 500 kHz MFINTOSC, 4 MHz HFINTOSC or
32 MHz PLL. The demonstration program has been modified to allow on-the-fly change
of frequency with unique delay routine and LCD write/erase values to allow best oper-
ation.
2.2.2.3 TEMPERATURE SETTINGS
Under the temperature settings the user will have the option to choose to display the
temperature or to toggle the temperature standard for the Active mode display. If the
user chooses the Display option, then the LCD will display the current temperature
reading from the temperature sensor (U3); or by using the POT [R9], the user can see
the full range of temperature readings in both Celsius and Fahrenheit temperature
standards. If the user selects Type, it will toggle between the Celsius and Fahrenheit
options. Whichever standard is selected under the Type option will be displayed on the
active display.
Note: It is important to note that when the user chooses any of these options, the
current time on the clock is used as a starting point. This means if the clock
displays 03:30:05 P, if under Set Alarm, the 30 minute nap will chime an
alarm at 04:00:05 P, the 60 minute nap at 04:30:05 P, and the Custom will
bring up 03:30:05 P on its display, allowing users to increment hours or min-
utes from that point. This will allow users to quickly set alarm times near the
clock base, as well as to ensure the alarm starts from the correct time base.
Sleep mode will not affect alarm set times, however, alarm times are depen-
dent upon the clock time, so this should be taken under consideration.