Intel PXA255 manual Read Configuration Register Programming Values, Memclk SDCLK0 Mdrefr

Models: PXA255

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Memory Controller

Table 6-17. Read Configuration Register Programming Values

Bits

Field Name

Value to Program

 

 

 

2:0

BURST LENGTH

010

8

Word Burst

 

 

 

 

 

5:3

reserved

000

 

 

 

 

6

CLOCK CONFIGURATION

1

 

Use rising edge of clock

 

 

 

 

 

 

 

 

1

 

7

BURST SEQUENCE

Linear burst Order

 

 

(INTEL BURST ORDER IS NOT SUPPORTED)

 

 

 

8

WAIT CONFIGURATION

N/A

nWAIT from the Flash device is ignored by the

 

 

processor.

 

 

 

 

9

DATA OUTPUT CONFIGURATION

0

 

Hold data for one clock

 

 

 

 

10

reserved

0

 

 

 

 

 

 

010 -> CAS Latency 3

 

 

011 -> CAS Latency 4

 

 

100 -> CAS Latency 5

13:11

FREQUENCY CONFIGURATION

101 -> CAS Latency 6

 

 

110 -> CAS Latency 7

 

 

Chosen based on the AC Characteristics - Read only

 

 

Operation section of the Flash device data sheet

 

 

 

 

14

reserved

0

 

 

 

 

 

15

READ MODE

0

- Synchronous Operation

1

- Asynchronous Operation

 

 

 

 

 

 

Table 6-18shows sample frequency configurations for programming non-SDRAM Timing Fast Flash. When in doubt, the higher frequency configuration and corresponding CAS latency must be used.

Table 6-18. Frequency Code Configuration Values Based on Clock Speed (Sheet 1 of 2)

MEMCLK

SDCLK0

 

MDREFR:

Valid

Corresponding

 

Frequency

Frequency

Frequency

 

K0DB2

CAS Latencies

 

Configurations

 

 

 

 

 

 

 

 

 

 

 

 

 

20

 

20

0

 

2 / 3 / 4 / 5 / 6

3 / 4 / 5 / 6 / 7

 

 

 

 

 

 

 

33

 

33

0

 

3 / 4 / 5 / 6

4 / 5 / 6 / 7

 

 

 

 

 

 

 

50

 

50

0

 

4 / 5 / 6

5 / 6 / 7

 

 

 

 

 

 

 

25

1

 

2 / 3 / 4 / 5 / 6

3 / 4 / 5 / 6 / 7

 

 

 

 

 

 

 

 

 

 

66

 

66

0

 

5 / 6

6 / 7

 

 

 

 

 

 

 

33

1

 

3 / 4 / 5 / 6

4 / 5 / 6 / 7

 

 

 

 

 

 

 

 

 

 

100

 

50

1

 

4 / 5 / 6

5 / 6 / 7

 

 

 

 

 

 

 

118

 

59

1

 

5 / 6

6 / 7

 

 

 

 

 

 

 

6-40

Intel® PXA255 Processor Developer’s Manual

Page 222
Image 222
Intel PXA255 manual Read Configuration Register Programming Values, Memclk SDCLK0 Mdrefr