Computer Hardware User Manual

www.ti.com

DDR2 Memory Controller Registers

4.7 Burst Priority Register (BPRIO)

The Burst Priority Register (BPRIO) helps prevent command starvation within the DDR2 memory

controller. To avoid command starvation, the DDR2 memory controller momentarily raises the priority of

the oldest command in the command FIFO after a set number of transfers have been made. The

PRIO_RAISE bit sets the number of transfers that must be made before the DDR2 memory controller

raises the priority of the oldest command. The BPRIO is shown in Figure 25 and described in Table 24.

For more details on command starvation, see Section 2.7.2.

Figure 25. Burst Priority Register (BPRIO)

31 16

Reserved

R-0

15 8 7 0

Reserved PRIO_RAISE

R-0 R/W-0xFF

LEGEND: R/W = Read/Write; R = Read only; -n = value after reset

Table 24. Burst Priority Register (BPRIO) Field Descriptions

Bit Field Value Description

31-8 Reserved 000h Reserved. The reserved bit location is always read as 0. A value written to this field has no effect.

7-0 PRIO_RAISE 0h 1 memory transfer.

1h 2 memory transfers.

...

FEh 255 memory transfers.

FFh EMIF reorders commands based on its arbitration.

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

Submit Documentation Feedback