4513_03 Datasheet, PDF (158/210 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.6 Voltage comparator
2.6.3 Notes on use
q Voltage comparator function
When the voltage comparator function is valid with the voltage comparator control register Q3, it is
operating even in the RAM back-up mode. Accordingly, be careful about such state because it
causes the increase of the operation current in the RAM back-up mode.
In order to reduce the operation current in the RAM back-up mode, invalidate (bits 2 and 3 of register
Q3 = “0”) the voltage comparator function by software before the POF instruction is executed.
Also, while the voltage comparator function is valid, current is always consumed by voltage comparator.
On the system required for the low-power dissipation, invalidate the voltage comparator when it is
unused by software.
q Register Q3
Bits 0 and 1 of register Q3 can be only read. Note that they cannot be written.
q Reading the comparison result of voltage comparator
Read the voltage comparator comparison result from register Q3 after the voltage comparator response
time (max. 20 µs) is passed from the voltage comparator function become valid.
4513/4514 Group User’s Manual
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