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AMD Geode™ LX Processors Data Book 35
Signal Definitions
33234H
3.4.3 Memory Interface Signals (DDR)
Signal Name Ball No. Type f V Description
SDCLK[5:0]P,
SDCLK[5:0]N
D20, D21,
D23, D24,
J28, H28,
M28, L28,
J4, H4,
M4, L4
O up to 200 MHz 2.5 SDRAM Clock Differential Pairs. The SDRAM
devices sample all the control, address, and
data based on these clocks. All clocks are dif-
ferential clock outputs.
MVREF P1 I Analog V
MEM
Memory Voltage Reference. This input oper-
ates at half the V
MEM
voltage.
CKE[1:0] F4, E4 I/O up to 200 Mb/s 2.5 Clock Enable. For normal operation, CKE is
held high. CKE goes low during Suspend.
CKE0 is used with CS0# and CS1#. CKE1 is
used with CS2# and CS3#.
CS[3:0]# D30, F29,
F28, B28
I/O up to 200 Mb/s 2.5 Chip Selects. The chip selects are used to
select the module bank within the system mem-
ory. Each chip select corresponds to a specific
module bank.
If CS# is high, the bank(s) do not respond to
RAS#, CAS#, or WE# until the bank is selected
again.
RAS[1:0]# D27, C26 I/O up to 200 Mb/s 2.5 Row Address Strobe. RAS#, CAS#, WE#, and
CKE are encoded to support the different
SDRAM commands. RAS0# is used with CS0#
and CS1#. RAS1# is used with CS2# and
CS3#.
CAS[1:0]# E29, E28 I/O up to 200 Mb/s 2.5 Column Address Strobe. RAS#, CAS#, WE#,
and CKE are encoded to support the different
SDRAM commands. CAS0# is used with CS0#
and CS1#. CAS1# is used with CS2# and
CS3#.
WE[1:0]# A28, C27 I/O up to 200 Mb/s 2.5 Write Enable. RAS#, CAS#, WE#, and CKE
are encoded to support the different SDRAM
commands. WE0# is used with CS0# and
CS1#. WE1# is used with CS2# and CS3#.
BA[1:0] C20, D26 I/O up to 200 Mb/s 2.5 Bank Address Bits. These bits are used to
select the component bank within the SDRAM.
MA[13:0] See Table
3-6 on
page 30
I/O up to 200 Mb/s 2.5 Memory Address Bus. The multiplexed row/
column address lines driven to the system
memory.
Supports 256-Mbit SDRAM.
TLA[1:0] B13, B15 I/O up to 200 Mb/s 2.5 Memory Debug Pins. These pins provide use-
ful memory interface debug timing signals.
(Should be wired to DIMM slot.)
TLA[0] is wired to DQS[8] on the DIMM
TLA[1] is wired to CB[0] on the DIMM
DQS[7:0] N31, J29,
B23, C19,
A10, C6,
H3, M2
I/O up to 200 MHz 2.5 DDR Data Strobe.