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17
17.4 Exiting RAM Backup Mode (Wakeup)
Processing to exit RAM backup mode and return to normal operation is referred to as "wakeup
processing." Figure 17.4.1 shows an example of wakeup processing. Wakeup processing is
initiated by reset input. The following shows how to execute wakeup processing.
(1) Reset the device (
(2) Set port X for output mode and output a high from the port (
(3) Check the RAM contents against the check data created before entering RAM backup mode
(
in Figure 17.4.1).
(4) If the RAM contents and check data did not match when checked in (3), initialize the RAM (
in Figure 17.4.1). If the RAM contents and check data matched, use the retained data in the
program.
(5) After initializing each internal circuit (
17.4.1).
Note : For wakeup from power outage RAM backup mode, settings for port X are unnecessary.
Note : For wakeup from power outage RAM backup mode, settings for port X are unnecessary.
Figure 17.4.1 Wakeup Processing
in Figure 17.4.1). For details about reset, refer to Chapter 7, "Reset."
in Figure 17.4.1), return the main routine (
Example of wakeup processing
Reset
Set transistor's base
connecting pin (port X) for
high-level output mode
(Note)
Check RAM contents
against backup RAM
check data
Error
Initialize RAM
Initial each internal circuit
To main routine
17-9
RAM BACKUP MODE
17.4 Exiting RAM Backup Mode (Wakeup)
in Figure 17.4.1).(Note)
OK
in Figure
Ver.0.10
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