PC MAIN CLOCK

1484A—04/28/09

ICS9LPRS525

PC MAIN CLOCK

2

Pin Description

PIN #

PIN NAME

TYPE

DESCRIPTION

1

PCI0/CR#_A

I/O

3.3V PCI clock output or Clock Request control A for either SRC0 or SRC2 pair

The power-up default is PCI0 output, but this pin may also be used as a Clock Request control of SRC pair 0 or SRC pair 2 via SMBus. Before

configuring this pin as a Clock Request Pin, the PCI output must first be disabled in byte 2, bit 0 of SMBus address space . After the PCI output is

disabled (high-Z), the pin can then be set to serve as a Clock Request pin for either SRC pair 2 or pair 0 using the CRA#_EN bit located in byte 5 of

SMBUs address space.

Byte 5, bit 7

0 = PCI0 enabled (default)

1= CRA# enabled. Byte 5, bit 6 controls whether CRA# controls SRC0 or SRC2 pair

Byte 5, bit 6

0 = CRA# controls SRC0 pair (default),

1= CRA# controls SRC2 pair

2

VDDPCI

PWR

Power supply for PCI clocks, nominal 3.3V

3

PCI1/CR#_B

I/O

3.3V PCI clock output/Clock Request control B for either SRC1 or SRC4 pair

The power-up default is PCI1 output, but this pin may also be used as a Clock Request control of SRC pair 1 or SRC pair 4 via SMBus. Before

configuring this pin as a Clock Request Pin, the PCI output must first be disabled in byte 2, bit 1 of SMBus address space . After the PCI output is

disabled (high-Z), the pin can then be set to serve as a Clock Request pin for either SRC pair 1 or pair 4 using the CRB#_EN bit located in byte 5 of

SMBUs address space.

Byte 5, bit 5

0 = PCI1 enabled (default)

1= CRB# enabled. Byte 5, bit 6 controls whether CRB# controls SRC1 or SRC4 pair

Byte 5, bit 4

0 = CRB# controls SRC1 pair (default)

1= CRB# controls SRC4 pair

4PCI2/TME

I/O

3.3V PCI clock output / Trusted Mode Enable(TME) Latched Input. This pin is sampled on power-up as follows

0=Overclocking of CPU and SRC allowed

1=Overclocking of CPU and SRC NOT allowed

After being sampled on power-up, this pin becomes a 3.3V PCI Output

5

PCI3/CFG0

I/O

3.3V PCI clock output/Configuration Strap. See PCI3 Configuration Table for more information

6

PCI4/SRC5_EN

I/O

3.3V PCI clock output / SRC5 pair or PCI_STOP#/CPU_STOP# enable strap. On powerup, the logic value on this pin determines if the SRC5 pair is

enabled or if CPU_STOP#/PCI_STOP# is enabled (pins 29 and 30). The latched value controls the pin function on pins 29 and 30 as follows

0 = PCI_STOP#/CPU_STOP#

1 = SRC5/SRC5#

7

PCI_F5/ITP_EN

I/O

Free running PCI clock output and ITP/SRC8 enable strap. This output is not affected by the state of the PCI_STOP# pin. On powerup, the state of

this pin determines whether pins 38 and 39 are an ITP or SRC pair.

0 =SRC8/SRC8#

1 = ITP/ITP#

8

GNDPCI

PWR

Ground pin for the PCI outputs

9

VDD48

PWR

Power pin for the 48MHz output and PLL.3.3V

10

USB_48MHz/FSLA

I/O

3.3V tolerant input for CPU frequency selection. Refer to input electrical characteristics for Vil_FS and Vih_FS values. / Fixed 48MHz USB clock

output. 3.3V.

11

GND48

PWR

Ground pin for the 48MHz outputs

12

VDD96IO

PWR

Power supply for DOT96 outputs, 1.05V to 3.3V.

13

DOTT_96_LRS/SRCT0_LRS

OUT

True clock of low power differential SRC or DOT96 with integrated 33 ohm Rs. The power-up default function is SRC0. After powerup, this pin function

may be changed to DOT96 via SMBus Byte 1, bit 7 as follows:

0= SRC0

1=DOT96

14

DOTC_96_LRS/SRCC0_LRS

OUT

Complement clock of low power differential SRC or DOT96 with integrated 33 ohm Rs. The power-up default function is SRC0#. After powerup, this

pin function may be changed to DOT96# via SMBus Byte 1, bit 7 as follows

0= SRC0#

1=DOT96#

15

GND

PWR

Ground pin.

16

VDD

PWR

Power supply, nominal 3.3V

17

SRCT1_LRS/SE1

OUT

True clock of low power differential SRC1 clock pair with integrated 33 ohm Rs. / 3.3V single-ended output. The powerup default is 100 MHz SRC, -

0.5% downspread. The pin function may be changed via SMBus B1b[4:1]

18

SRCC1_LRS/SE2

OUT

Complement clock of low powerl differential SRC1 clock pair with integrated 33 ohm Rs / 3.3V single-ended output. The powerup default is 100 MHz

SRC, -0.5% downspread. The pin function may be changed via SMBus B1b[4:1]

19

GND

PWR

Ground pin.

20

VDDPLL3IO

PWR

Power supply for PLL3 outputs. 1.05V to 3.3V.

21

SRCT2_LRS/SATAT_LRS

OUT

True clock of low power differentiall SRC/SATA clock pair with integrated Rs.

22

SRCC2_LRS/SATAC_LRS

OUT

Complement clock of low power differential push-pull SRC/SATA clock pair with integrated 33 ohm Rs.

23

GNDSRC

PWR

Ground pin for the SRC outputs

24

SRCT3_LRS/CR#_C

I/O

True clock of low power differential SRC clock pair with integrated 33 ohm Rs./ Clock Request control C for either SRC0 or SRC2 pair. The power-up

default is SRCCLK3 output, but this pin may also be used as a Clock Request control of SRC pair 0 or SRC pair 2 via SMBus. Before configuring this

pin as a Clock Request Pin, the SRC output must first be disabled in byte 4, bit 7 of SMBus address space . After the SRC output is disabled, the pin

can then be set to serve as a Clock Request pin for either SRC pair 2 or pair 0 using the CRC#_EN bit located in byte 5 of SMBUs address space.

Byte 5, bit 3

0 = SRCCLK3 enabled (default)

1= CRC# enabled. Byte 5, bit 2 controls whether CRC# controls SRC0 or SRC2 pair

Byte 5, bit 2

0 = CRC# controls SRC0 pair (default),

1= CRC# controls SRC2 pair