4513_03 Datasheet, PDF (74/210 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCOMPUTER

16 _{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 ex-
ecuted.
Also, while the voltage comparator function is valid, current is al-
ways consumed by voltage comparator. On the system required
for the low-power dissipation, invalidate the voltage comparator
when it is unused by software.
17 Register Q3
Bits 0 and 1 of register Q3 can be only read. Note that they can-
not be written.
18 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.
HARDWARE
LIST OF PRECAUTIONS
4513/4514 Group User’s Manual
1-61