4513 datasheet(158/210 Pages) RENESAS

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APPLICATION

2.6 Voltage comparator

2-55

4513/4514 Group User’s Manual

2.6.3 Notes on use

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.

Bits 0 and 1 of register Q3 can be only read. Note that they cannot be written.

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 Datasheet(PDF) 158 Page - Renesas Technology Corp