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8355 N/B MAINTENANCE
8355 N/B MAINTENANCE
100
DDR SDRAM Memory Interface
Signal Name Type Description
MEMCLK_H/L[7]
O-IOD Differential DDR SDRAM clock to the top of DIMM 0 for
unbuffered DIMMs.
1
MEMCLK_H/L[6]
O-IOD Differential DDR SDRAM clock to the top of DIMM 0 for
unbuffered DIMMs.
1
MEMCLK_H/L[5]
O-IOD Differential DDR SDRAM clock to the bottom of DIMM 0 for
unbuffered DIMMs.
1
MEMCLK_H/L[4]
O-IOD Differential DDR SDRAM clock to the bottom of DIMM 0 for
unbuffered DIMMs.
1
MEMCLK_H/L[3]
O-IOD Differential DDR SDRAM clock to DIMM 3 for registered
DIMMs.
1
MEMCLK_H/L[2]
O-IOD Differential DDR SDRAM clock to DIMM 3 for registered
DIMMs.
1
MEMCLK_H/L[1]
O-IOD Differential DDR SDRAM clock to the middle of DIMM 1 for
unbuffered DIMMs, or DIMM 1 for registered DIMMs.
1
MEMCLK_H/L[0]
O-IOD Differential DDR SDRAM clock to the middle of DIMM 1 for
unbuffered DIMMs, or DIMM 1 for registered DIMMs.
1
MEMCKEA
MEMCKEB
O-IOS
Clock Enables to DIMMs. Used to gate clocks for power
management functionality.
1
MEMDQS[17:0]
B-IOS
DRAM Data Strobes synchronous with MEMDATA and
MEMCHECK during DRAM read and writes.
1
MEMDATA[63:0]
B-IOS DRAM Interface Data Bus
MEMCHECK[7:0]
B-IOS DRAM Interface ECC Check Bits
MEMCS_L[7:0]
O-IOS DRAM Chip Selects
1
MEMRASA_L
MEMRASB_L
O-IOS
DRAM Row Address Select. MEMRASA_L and
MEMRASB_L are functionally identical. Two copies are
provided to accommodate the loading of unbuffered DIMMs.
1
MEMCASA_L
MEMCASB_L
O-IOS
DRAM Column Address Select. MEMCASA_L and
MEMCASB_L are functionally identical. Two copies are
provided to accommodate the loading of unbuffered DIMMs.1
MEMWEA_L
MEMWEB_L
O-IOS
DRAM Write Enable. MEMWEA_L and MEMWEB_L are
functionally identical.
Two copies are provided to accommodate the loading of
unbuffered DIMMs.
1
MEMADDA[13:0]
MEMADDB[13:0]
O-IOS
DRAM Column/Row Address. Two copies are provided to
accommodate the loading of unbuffered DIMMs. During
precharges, activates, reads, and writes, the two copies
are inverted from each other (except A[10] which is used for
auto-precharge) to minimize switching noise. The signals are
inverted only when the bus is used to carry address
information.
1
DDR SDRAM Memory Interface Continue
Signal Name Type Description
MEMBANKA[1:0]
MEMBANKB[1:0]
O-IOS
DRAM Bank Address. Two copies are provided to
accommodate the loading of unbuffered DIMMs. During
precharges, activates, reads, and writes the two copies are
inverted from each other to minimize switching noise. The
signals are inverted only when the bus is used to carry address
information.
1
MEMRESET_L
O-IOS
DRAM Reset pin for Suspend-to-RAM power management
mode. This pin is required for registered DIMMs only.
MEMVREF
VREF DRAM Interface Voltage Reference
1
MEMZP
A Compensation Resistor tied to VSS
1
MEMZN
A Compensation Resistor tied to 2.5 V
1
Notes:
1. For connection details and proper resistor values, see the AMD Athlon™ 64 Processor Motherboard
Design Guide, order# 24665.
JTAG Pin Descriptions
Signal Name Type Description
TCK
I-IOS JTAG Clock
TMS
I-IOS JTAG Mode Select
TRST_L
I-IOS JTAG Reset
TDI
I-IOS JTAG Data Input
TDO
O-IOS JTAG Data Output
Clock
Signal Name Type Description
CLKIN_H/L
I-IOD 200-MHz PLL Reference Clock
FBCLKOUT_H/L
O-IOD Core Clock PLL 200-MHz Feedback Clock
5. Pin Descriptions of Major Components
5.1 AMD ATHLON
TM
64 Processor-1