EP80579 Datasheet, PDF (300/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
11.4.2.1 ODT Control of Reads
During a read command in a 2 slot configuration as shown in Figure 11-4, the memory
controller will enable ODT on the inactive slot. The ODT pin will be asserted by the
controller such that the termination in the inactive slot will be enabled 1 tCK before the
active slot starts driving the DQ bus. The termination will be turned-off by the
controller ½ tCK after the last DQ is driven by the active slot as show in Figure 11-4.
There is no assertion of the ODT signal to the DRAM device in a 1 slot configuration.
Please refer the Section 16.1.1.49, “Offset B0h: DDR2ODTC - DDR2 ODT Control
Register” for more details on the CSR that needs to be programmed by BIOS so that
the memory controller drives the proper ODT control signals.
Figure 11-4. ODT Timing on Back-to-Back Reads to Different Slots
0
1
2
3
4
5
6
7
8
Read A
Slot 1
ODT
Slot 2
ODT
Slot 1
DQ
Slot 2
Rtt
Slot 1
Rtt
CL = 4
tOND = 2 tCK
Read A
Slot 2
CL = 4
BL = 4
Termination ON Slot 2
tONF = 2.5 tCK
tOND = 2 tCK
BL = 4
Termination ON Slot 1
tONF = 2.5 tCK
11.4.2.2
ODT Control of Writes
During a write command in a 2 slot configuration as shown in Figure 11-5, the EP80579
memory controller will enable ODT on the inactive slot. The ODT pin will asserted by
the controller such that the termination in the inactive slot will be enabled 1 tCK before
the controller starts driving the DQ bus (except for configurations where CL = 3). The
termination will be turned-off by the controller ½ tCK after the last DQ is driven by the
controller to the active slot as shown in Figure 11-5.
During a write command in a one slot configuration, the memory controller will enable
ODT to the active slot such that the termination is enabled 1 tCK before the controller
starts driving the DQ bus (except for configurations where CL = 3, see note below).
Intel^® EP80579 Integrated Processor Product Line Datasheet
300
August 2009
Order Number: 320066-003US