82801DB datasheet(49/587 Pages) INTEL

49 / 587 page

Intel® 82801DB ICH4 Datasheet

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.

RTCX2

Special

Crystal Input 2: This signal is connected to the 32.768 kHz crystal.

Table 2-15. Other Clocks

Name

Type

Description

CLK14

Oscillator Clock: This clock is used for 8254 timers. It runs at 14.31818 MHz.

This clock is permitted to stop during S3 (or lower) states

CLK48

48 MHz Clock: This clock is used to run the USB controllers. It runs at 48

MHz. This clock is permitted to stop during S3 (or lower) states

CLK66

66 MHz Clock: This clock is used to run the hub interface. It runs at 66 MHz.

This clock is permitted to stop during S3 (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 0.

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

See Section 2.20.1 for more details. There is a weak integrated pull-

down resistor on SPKR pin.

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).

NOTES:

1. Clearing CMOS in an Intel® ICH4-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.

2. Unless entering the XOR Chain Test Mode, the RTCRST# input must

always be high when all other RTC power planes are on.

TP[0]

Test Point: This signal must have an external pull-up to VccSus3_3.

82801DB Datasheet(PDF) 49 Page - Intel Corporation

82801DB Datasheet(HTML) 49 Page - Intel Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL