Power-Down - Husky MP2500 Manual

32.1.1.4 RTC alarm
The RTC alarm is set by using INT 1AH, function 6. When the RTC time
matches the RTC alarm time, it will turn MP2500 on. You can disable the
alarm by using INT 1AH function 07H.
The easiest way to check if the alarm has caused the power up is to enable
the alarm event (using INT 15H function 6EH) before power down, then
check the event details on power up, using INT 15H function 6DH.
(Another, more laborious, way is to read the RTC time and alarm time,
using INT 1AH functions 02H and 09H, and compare them.)

32.1.2 Power-down

While turned off, MP2500 will normally remember the current execution
state so that it can restore it when turned on again. This is called 'resume
mode'. Resume mode can be disabled by using INT 15H, function 64H, and
will be cancelled if all battery power has been exhausted (ie including the
backup battery).
MP2500 can power down when:
•
The user presses the P key.
•
The keyboard has not been touched for a period exceeding the idle
timeout.
•
The power-down function (INT 15H, function 68H) is used.
•
The battery voltage falls below approximately 3.3V.
•
The battery voltage falls below approximately 2.6V to 2.7V (this could
be caused by a totally flat battery, power loss, removal of batteries, or
an excessive peripheral power load).
With the exception of the last two conditions, all these causes can be
enabled, modified, or disabled under program control. This allows programs
to ensure that crucial tasks (such as transmitting or saving a file) are
completed before power-down.
Chapter 32: Using Power Handling 303