82801BA datasheet(47/498 Pages) INTEL

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82801BA ICH2 and 82801BAM ICH2-M Datasheet

2-11

Signal Description

2.14

Real Time Clock Interface

2.15

Other Clocks

2.16

Miscellaneous Signals

Table 2-14. Real Time Clock Interface

Name

Type

Description

RTCX1

Special

Crystal Input 1: This signal is connected to the 32.768 KHz crystal. If no

external crystal is used, then RTCX1 can be driven with the desired clock rate.

RTCX2

Special

Crystal Input 2: This signal is connected to the 32.768 KHz crystal. If no

external crystal is used, then RTCX2 should be left floating.

Table 2-15. Other Clocks

Name

Type

Description

CLK14

Oscillator Clock: CLK14 is used for 8254 timers and runs at 14.31818 MHz.

82801BA ICH2: This clock is permitted to stop during S3 (or lower) states.

82801BAM ICH2-M: This clock is permitted to stop during S1 (or lower) states.

CLK48

48 MHz Clock: CLK48 is used to for the USB controller and runs at 48 MHz.

82801BA ICH2: This clock is permitted to stop during S3 (or lower) states.

82801BAM ICH2-M: This clock is permitted to stop during S1 (or lower) states.

CLK66

66 MHz Clock: CLK66 is used to for the hub interface and runs at 66 MHz.

82801BA ICH2: This clock is permitted to stop during S3 (or lower) states.

82801BAM ICH2-M: This clock is permitted to stop during S1 (or lower) states.

Table 2-16. Miscellaneous Signals

Name

Type

Description

SPKR

Speaker: The SPKR signal is the output of counter 2 and is internally "ANDed"

with Port 61h bit 1 to provide Speaker Data Enable. This signal drives an external

speaker driver device, which in turn drives the system speaker. Upon PCIRST#, its

output state is 1.

Note: SPKR is sampled at the rising edge of PWROK as a functional strap. See

Section 2.20.1for more details.

RTCRST#

RTC Reset: When asserted, this signal resets register bits in the RTC well and

sets the RTC_PWR_STS bit (bit 2 in GEN_PMCON3 register). This signal is also

used to enter the test modes documented in Section 2.20.2.

Note: Clearing CMOS in an ICH2-based platform can be done by using a jumper

on RTCRST# or GPI, or using SAFEMODE strap. Implementations should not

attempt to clear CMOS by using a jumper to pull VccRTC low.

TP0

(ICH2 0nly)

Test Point (82801BA ICH2): This signal must have an external pull-up to

VccSus3_3.

FS0

Functional Strap: This signal is reserved for future use. There is an internal pull-

up resistor on this signal.

82801BA Datasheet(PDF) 47 Page - Intel Corporation

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