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DDR2 Memory Controller Registers

4.11 DDR PHY Control Register (DDRPHYCR)

The DDR PHY control register (DDRPHYCR) configures the DDR2 memory controller DLL for operation and determines whether the DLL is in reset, whether it is powered up, and the read latency. The DDRPHYCR is shown in Figure 29 and described in Table 35.

Figure 29. DDR PHY Control Register (DDRPHYCR)

31

 

 

 

 

 

16

 

Reserved

 

 

 

 

 

 

R/W-5000h

 

 

 

 

 

15

6

5

4

3

2

0

Reserved

 

DLLRESET

DLLPWRDN

Rsvd

 

READLAT

R/W-190h

 

R/W-0

R/W-1

R-1

 

R/W-7h

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

Table 35. DDR PHY Control Register (DDRPHYCR) Field Descriptions

Bit

Field

Value

Description

31-16

Reserved

5000h

Reserved. Always write 5000h to these bits.

15-6

Reserved

190h

Reserved. Always write 190h to these bits.

5

DLLRESET

 

Reset DLL.

 

 

0

DLL is out of reset.

 

 

1

Places the DLL in reset.

4

DLLPWRDN

 

Power down DLL.

 

 

0

DLL is powered up.

 

 

1

DLL is powered down, if DLLPWRDN and the SR bit and MCLKSTOPEN bit in the SDRAM

 

 

 

refresh control register (SDRCR) are set to 1.

3

Reserved

1

Reserved

2-0

READLAT

0-7h

Read latency. Read latency is equal to CAS latency plus round trip board delay for data

 

 

 

minus 1. The maximum value of read latency that is supported is CAS latency plus 3. The

 

 

 

minimum read latency value that is supported is CAS latency plus 1. The read latency value

 

 

 

is defined in number of MCLK/DDR_CLK cycles.

52

DDR2 Memory Controller

SPRU986B–November 2007

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Texas Instruments TMS320DM643 manual DDR PHY Control Register Ddrphycr Field Descriptions