Computer Hardware User Manual

DCAB

DDR2CLKOUT

DCE0

DSDCKE

DSDRAS

DSDWE

DSDDQM[3:0]

DSDCAS

DBA[2:0]

DEA[13:11,9:0]

DEA[10]

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Peripheral Architecture

2.4.4 Deactivation (DCAB and DEAC)

The precharge all banks command (DCAB) is performed after a reset to the DDR2 memory controller or

following the initialization sequence. DDR2 SDRAMs also require this cycle prior to a refresh (REFR) and

mode set register commands (MRS and EMRS). During a DCAB command, DEA10 is driven high to

ensure the deactivation of all banks. Figure 6 shows the timing diagram for a DCAB command.

Figure 6. DCAB Command

SPRU970G– December 2005– Revised June 2011 C6455/C6454 DDR2 Memory Controller

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