
CHAPTER 2 PIN FUNCTIONS
65
2.2.2 Clock Interface Signals
These signals are used to supply clocks. Table 2-2 lists functions of these signals.
Table 2-2. Clock Interface Signals
Signal
I/O
Description of function
RTCX1
I
This is the 32.768-kHz oscillator’s input pin. It is connected to one side of a crystal resonator.
RTCX2
O
This is the 32.768-kHz oscillator’s output pin. It is connected to one side of a crystal resonator.
CLKX1
I
This is the 18.432-MHz oscillator’s input pin. It is connected to one side of a crystal resonator.
CLKX2
O
This is the 18.432-MHz oscillator’s output pin. It is connected to one side of a crystal resonator.
FIRCLK
I
This the 48-MHz clock input pin. Fix this at high level when FIR is not used.
2.2.3 Battery Monitor Interface Signals
These signals indicate when an external agent is able to provide enough power for system operations. Table 2-3
describes the functions of these signals.
Table 2-3. Battery Monitor Interface Signals
Signal
I/O
Description of function
BATTINH/
BATTINT#
I
This function differs depending on how the MPOWER pin is set.
<When MPOWER = 0>
BATTINH function
This is an interrupt signal that is output when remaining power is low while battery is ON. The
external agent checks the remaining battery power and asserts the signal at this pin if the supplied
voltage is sufficient for current operations.
1 : Battery OK
0 : Battery low
<When MPOWER = 1>
BATTINT# function
This is an interrupt signal that is output when remaining power is low during normal operations. The
external agent checks the remaining battery power and asserts the signal at this pin if voltage
sufficient for operations cannot be supplied.