Oki Dr.63514, User Manual, Page: 62 / 101

Chapter 2. Functions
2-41
2.12 Backup Switching
The ML63512/514 includes a built-in backup circuit that doubles the power-supply voltage. The backup
circuit is used when the positive power-supply voltage (VDD) falls below 1.8 V. The Dr.63514 in-circuit
emulator includes an ML63514 to implement the level detector and comparator functions. The positive
power-supply voltage (VDD) in this ML63514 depends on the setting of the VDD.SEL switch, and has
the same external input voltage range as the ML63512/514, namely 0.9 to 5.5 V. The backup circuit
on/off setting for the ML63514 used in the Dr.63514 in-circuit emulator must be set appropriately as
well. The BACKUP switch sets the backup state of the ML63514 used in the Dr.63514 in-circuit
emulator.
operating condition for the operating voltage Backup Switch
1.5 V internally or 0.9 to 1.8 V externally ON
1.8 to 5.5 V externally OFF
ON
OFF
ON
OFF
BACKUP
38400 19200 9600 4800
SETICE
48/64 CMP
Figure 2-19 Backup Switch
n
Note 1
n
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This BACKUP switch is completely unrelated to the backup function of the ML63512/514 being
evaluated. The ML63512/514 backup function is implemented using only the BUPCON register
in the Dr.63514 in-circuit emulator.
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Caution
The BACKUP switch must be set to the operating
voltage used. If the switch is set to the wrong position,
the ML63514 used in the Dr.63514 in-circuit emulator
may be destroyed.