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DDR2 Memory Controller Registers

 

Table 20. SDRAM Configuration Register (SDCFG) Field Descriptions (continued)

Bit

Field

Value

Description

11-9

CL

 

CAS latency. The value of this field defines the CAS latency, to be used when accessing connected

 

 

 

SDRAM devices. A write to this field will cause the DDR2 Memory Controller to start the SDRAM

 

 

 

initialization sequence. This field is writeable only when the TIMUNLOCK bit is unlocked. Values 0,

 

 

 

1, 6, and 7 are reserved for this field.

 

 

2

CAS latency of 2

 

 

3

CAS latency of 3

 

 

4

CAS latency of 4

 

 

5

CAS latency of 5

8-7

Reserved

 

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

6-4

IBANK

 

Internal SDRAM bank setup bits. Defines number of banks inside connected SDRAM devices. A

 

 

 

write to this bit will cause the DDR2 Memory Controller to start the SDRAM initialization sequence.

 

 

 

Values 4-7 are reserved for this field.

 

 

0

One bank SDRAM devices

 

 

1

Two banks SDRAM devices

 

 

2

Four banks SDRAM devices

 

 

3

Eight banks SDRAM devices

3

Reserved

 

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

2-0

PAGESIZE

 

Page size bits. Defines the internal page size of the external DDR2 memory. A write to this bit will

 

 

 

cause the DDR2 Memory Controller to start the SDRAM initialization sequence. Values 0, 1, 6, and

 

 

 

7 are reserved for this field. Values 4-7 are reserved for this field.

 

 

0

256-word page requiring 8 column address bits.

 

 

1

512-word page requiring 9 column address bits.

 

 

2

1024-word page requiring 10 column address bits.

 

 

3

2048-word page requiring 11 column address bits.

SPRUEK5A –October 2007

DSP DDR2 Memory Controller

39

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Texas Instruments DM648 DSP, TMS320DM647 manual Sdram Configuration Register Sdcfg Field Descriptions