Figure 16-1illustrates the parameters used to describe memory access time.

delay

capacitive loading

setup time data to clock

Figure 16-1. Parameters Used to Describe Memory Access Time

Table 16-2lists the delays in gross memory access time for several values of VDD.

Table 16-2. Data and Clock Delays VDD ±10%, Temp, -40°C–+85°C (maximum)

 

Clock to Address Output Delay

Data Setup

Spectrum Spreader Delay

 

 

(ns)

 

(ns)

VDD

 

 

 

Time Delay

 

 

 

 

 

Normal

Strong

 

30 pF

60 pF

90 pF

(ns)

 

 

no dbl/dbl

no dbl/dbl

 

 

 

 

 

3.3

6

8

11

1

3/4.5

4.5/9

 

 

 

 

 

 

 

2.7

7

10

13

1.5

3.5/5.5

5.5/11

 

 

 

 

 

 

 

2.5

8

11

15

1.5

4/6

6/12

 

 

 

 

 

 

 

1.8

18

24

33

3

8/12

11/22

 

 

 

 

 

 

 

When the spectrum spreader is enabled with the clock doubler, every other clock cycle is shortened (sometimes lengthened) by a maximum amount given in the table above. The shortening takes place by shortening the high part of the clock. If the doubler is not enabled, then every clock is shortened during the low part of the clock period. The maxi- mum shortening for a pair of clocks combined is shown in the table.

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Rabbit 3000 Microprocessor

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Jameco Electronics 2000, 3000 manual Data and Clock Delays VDD ±10%, Temp, -40C-+85C maximum, Vdd