AM1808 datasheet(21/264 Pages) TI

21 / 264 page

AM1808

www.ti.com

SPRS653 – FEBRUARY 2010

3.7.3

Real-Time Clock and 32-kHz Oscillator

Table 3-5. Real-Time Clock (RTC) and 1.2-V, 32-kHz Oscillator Terminal Functions

SIGNAL

POWER

TYPE(1)

PULL(2)

DESCRIPTION

GROUP(3)

NAME

NO.

RTC_XI

J19

—

RTC 32-kHz oscillator input

RTC_XO

H19

—

RTC 32-kHz oscillator output

RTC_ALARM / UART2_CTS / GP0[8] / DEEPSLEEP

CP[0]

RTC Alarm

RTC module core power

RTC_CVDD

L14

PWR

—

(isolated from chip CVDD)

RTC_Vss

H18

GND

—

Oscillator ground (for filter)

(1)

I = Input, O = Output, I/O = Bidirectional, Z = High impedance, PWR = Supply voltage, GND = Ground, A = Analog signal.

Note: For multiplexed pins where functions have different types (ie., input versus output), the table reflects the pin function direction for

that particular peripheral.

(2)

IPD = Internal Pulldown resistor; IPU = Internal Pullup resistor; CP[n] = configurable pull-up/pull-down (where n is the pin group) using

the PUPDENA and PUPDSEL registers in the System Module. The pull-up and pull-down control of these pins is not active until the

device is out of reset. During reset, all of the pins associated with these registers are weakly pulled down. If the application requires a

pull-up, an external pull-up can be used.

(3)

This signal is part of a dual-voltage IO group (A, B or C). These groups can be operated at 3.3V or 1.8V nominal. The three groups can

be operated at independent voltages but all pins withina group will operate at the same voltage. Group A operates at the voltage of

power supply DVDD3318_A. Group B operates at the voltage of power supply DVDD3318_B. Group C operates at the voltage of power

supply DVDD3318_C.

3.7.4

DEEPSLEEP Power Control

Table 3-6. DEEPSLEEP Power Control Terminal Functions