Transparent Mode
Data from the tester is 16 bits wide at 200 MHz (single data rate). The data rate is
doubled and the width halved on the way to the DRAM (by clocking out 8 bits of data on
the rising edge of the clock and the remaining 8 bits on the falling edge).
The tester will drive data to be written to the DRAM on a write pass and data to be
compared on a read. DRAM data and the expected data from the tester is compared in
the AMB. If the actual and expected data differ the pass/fail outputs will indicate which
DRAM failed.
10.1.1
Block Diagram
The data paths for transparent mode will bypass all link logic and normal DRAM control
logic. The DDR interfaces are used intact. Figure 10-2 is a block diagram of the Intel
6400/6402 Advanced Memory Buffer (AMB) in transparent mode.
Figure 10-2. Block Diagram for the AMB in transparent mode
SET
SET
CLR
D
D
Q
Q
D
Q
Q
DRAM CMD/ADD
TCMD/TADD
CLR
SET
Shift Register
Q
Q
TDRV
Controlled by AMB CL, AL
or hard coded for WL=3
ENB
SET
CLR
D
Q
Q
CLR
SET
Multiplexer
D
Q
Q
TDQ
S1
D
16
144
CLR
S2
ENB
SET
CLR
D
Q
Q
C
ENB
DFTDATA
DRAMWR
DRAM DQ
DRAM DQS
Multiplexer
SET
CLR
Q
Q
D
Status
D
S1
DDR IO Read
Data FIFO
SET
CLR
Q
D
16
S2
Q
ENB
C
ENDOUT, DRAMRD
Read Pointer
Shift Register
Controlled by AMB CL, AL, CMD2DATA
or hard coded to RL=4 and CMD2DATA=4
SET
CLR
D
Q
Q
TCMP
ENB
10.1.2
Transparent Mode Signal Definitions
When the transparent mode is enabled. The FBD (Fully-Buffered DIMM) differential
input pins designed in the AMB part become two single ended inputs. In transparent
mode the FBD input pins require 0 to 500 mV swing (half of the normal differential
input voltage). Input slew rates should be approximately 5 V/ns. This parameter is not
critical, but it must be fast enough to be recognized by the AMB receiver. The DDR pins
will operate with normal DDR2 timings and levels.
The AMB clock input pins will be used for transparent mode as well as normal mode.
This also allows use of most of the existing on-chip clock distribution network.
100
Intel® 6400/6402 Advanced Memory Buffer Datasheet
INTEL [ INTEL ]
