Functional Description

Table 3-2. PowerPC 60x Bus to DRAM Access Timing — 70ns Page Devices

 

 

Clock Periods Required For:

 

Total

Access Type

 

 

 

 

 

 

1st

 

2nd

3rd

 

4th

 

 

Clocks

 

 

 

 

Beat

 

Beat

Beat

 

Beat

 

 

 

 

 

 

 

 

 

4-Beat Read after Idle (Quad-

10

 

1

3

 

1

15

word aligned)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4-Beat Read after Idle (Quad-

10

 

4

1

 

1

16

word misaligned)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4-Beat Read after 4-Beat Read

9/3 1

 

1

3

 

1

14/8

(Quad-word aligned)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4-Beat Read after 4-Beat Read

7/2 1

 

4

1

 

1

13/8

(misaligned)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4-Beat Write after Idle

4

 

1

1

 

1

7

 

 

 

 

4-Beat Write after 4-Beat Write

10/6 1

 

1

1

 

1

13/9

(Quad-word aligned)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1-Beat Read after Idle

10

 

-

-

 

-

10

 

 

 

 

1-Beat Read after 1-Beat Read

11/7 1

 

-

-

 

-

11/7

1-Beat Write after Idle

4

 

-

-

 

-

4

 

 

 

 

 

1-Beat Write after 1-Beat Write

1

-

-

 

-

15/11

15/11

 

 

 

 

 

 

 

 

 

Notes

1.These numbers assume that the PowerPC 60x bus master is doing address pipelining with TS_ occurring at the minimum time after AACK_ is asserted. Also, the two numbers shown in the 1st Beat column are for page miss/page hit.

2.In some cases, the numbers shown are averages and specific instances may be longer or shorter.

3

http://www.motorola.com/computer/literature

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Motorola MVME2300 Series manual PowerPC 60x Bus to Dram Access Timing 70ns Page Devices, 2nd 3rd 4th, Beat