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Motorola MVME2400 User Manual

Page 68

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3-20

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Functional Description

3

Note: The information in Table 3-10 is appropriate when configured with
devices with an access time equal to 12 CLK periods.

Note: The information in Table 3-11 is appropriate when configured with
devices with an access time equal to 8 CLK periods.

Table 3-10. PPC Bus to ROM/Flash Access Timing (120ns @ 100MHz)

ACCESS TYPE

CLOCK PERIODS REQUIRED FOR:

Total

Clocks

1st Beat

2nd Beat

3rd Beat

4th Beat

16

Bits

64

Bits

16

Bits

64

Bits

16

Bits

64

Bits

16

Bits

64

Bits

16

Bits

64

Bits

4-Beat Read

70

22

64

16

64

16

64

16

262

70

4-Beat Write

N/A

N/A

1-Beat Read (1 byte)

22

22

-

-

-

-

-

-

22

22

1-Beat Read (2 to 8 bytes)

70

22

-

-

-

-

-

-

70

22

1-Beat Write

21

21

-

-

-

-

-

-

21

21

Table 3-11. PPC Bus to ROM/Flash Access Timing (80ns @ 100MHz)

ACCESS TYPE

CLOCK PERIODS REQUIRED FOR:

Total

Clocks

1st Beat

2nd Beat

3rd Beat

4th Beat

16

Bits

64

Bits

16

Bits

64

Bits

16

Bits

64

Bits

16

Bits

64

Bits

16

Bits

64

Bits

4-Beat Read

54

18

48

12

48

12

48

12

198

54

4-Beat Write

N/A

N/A

1-Beat Read (1 byte)

18

18

-

-

-

-

-

-

18

18

1-Beat Read (2 to 8 bytes)

54

18

-

-

-

-

-

-

54

18

1-Beat Write

21

21

-

-

-

-

-

-

21

21