Intel 925 Data Sheet - Page 28

Signal Description R 2.4 DDR2 DRAM Reference and Compensation 2.5 Signal Name SRCOMP[1:0] SOCOMP[1:0] SM_SLEWIN[1:0] SM_SLEWOUT[1:0] SMVREF[1:0] Type Description I/O System Memory RCOMP I/O DDR2 On-Die DRAM Over Current Detection (OCD) driver A compensation I Buffer Slew Rate Input: Slew Rate Characterization buffer input for X and Y orientation. A O Buffer Slew Rate Output: Slew Rate Characterization buffer output for X and Y orientation A I SDRAM Reference Voltage: Reference voltage inputs for each DQ, DM, DQS, and DQS# input signals. A PCI Express* x16 Graphics Port Signals Unless otherwise specified, PCI Express Graphics signals are AC coupled, so the only voltage specified is a maximum 1.2 V differential swing. Signal Name EXP_RXN[15:0] EXP_RXP[15:0] EXP_TXN[15:0] EXP_TXP[15:0] EXP_COMPO EXP_COMPI EXP_SLR Type I/O PCIE O PCIE I A I A I CMOS Description PCI Express Graphics Receive Differential Pair PCI Express Graphics Transmit Differential Pair PCI Express Graphics Output Current Compensation Note: EXP_COMP0 is used for DMI current compensation. PCI Express Graphics Input Current Compensation Note: EXP_COMPI is used for DMI current compensation. PCI Express* Static Lane Reversal: The MCH's PCI Express lane numbers are reversed. For example, the MCH PCI Express interface signals can be configured as follows: Normal Lane Ball Operation Reversed C10 EXP_TXP0 EXP_TXP15 A9 EXP_TXP1 EXP_TXP14 ... ... ... N3 EXP_TXP14... EXP_TXP1... P1 EXP_TXP15 EXP_TXP0 0 = MCH's PCI Express lane numbers are reversed 1 = Normal operation 28 Intel® 82925X/82925XE MCH Datasheet