CHAPTER 2 PIN FUNCTIONS
User’s Manual U14272EJ3V0UM
55
2.2.3 Initialization interface signals
Signal name
I/O
Description of function
POWER
Input
V
R
4181 activation signal.
RSTSW#
Input
V
R
4181 reset signal.
RTCRST#
Input
Reset signal for internal Real-time clock and internal logic. When power is first
supplied to the system, the external agent must activate this signal.
POWERON
Output
This signal indicates that the V
R
4181 is ready to operate. It becomes active when a
power-on factor is detected and becomes inactive when the BATTINH/BATTINT#
signal check has been completed.
MPOWER
Output
This signal indicates that the V
R
4181 is operating. This signal is inactive during
Hibernate mode. During this signal being inactive, turn off the 2.5 V power supply.
2.2.4 Battery monitor interface signals
Signal name
I/O
Description of function
BATTINH/BATTINT#
Input
The function of this pin differs depending on the state of the MPOWER pin.
<When MPOWER = 0>
BATTINH signal
Enables or disables activation on power application.
1: Enable activation
0: Disable activation
<When MPOWER = 1>
BATTINT# signal
This is an interrupt signal that is input when remaining battery power is low during
normal operations. The external agent checks the remaining battery power and
activates this signal if voltage sufficient for operations cannot be supplied.
2.2.5 Clock interface signals
Signal name
I/O
Description of function
RTCX(2:1)
−
Connections to 32.768 kHz crystal resonator.
CLKX(2:1)
−
Connections to 18.432 MHz crystal resonator.
