82801BA Datasheet, PDF (47/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Signal Description
2.14 Real Time Clock Interface
Table 2-14. Real Time Clock Interface
Name
RTCX1
RTCX2
Type
Description
Special
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.
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.
2.15 Other Clocks
Table 2-15. Other Clocks
Name
Type
Description
CLK14
CLK48
CLK66
Oscillator Clock: CLK14 is used for 8254 timers and runs at 14.31818 MHz.
I 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.
48 MHz Clock: CLK48 is used to for the USB controller and runs at 48 MHz.
I 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.
66 MHz Clock: CLK66 is used to for the hub interface and runs at 66 MHz.
I 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.
2.16 Miscellaneous Signals
Table 2-16. Miscellaneous Signals
Name
Type
Description
SPKR
RTCRST#
TP0
(ICH2 0nly)
FS0
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
O _{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.
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.
I
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.
I
Test Point (82801BA ICH2): This signal must have an external pull-up to
VccSus3_3.
I
Functional Strap: This signal is reserved for future use. There is an internal pull-
up resistor on this signal.
82801BA ICH2 and 82801BAM ICH2-M Datasheet
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