Use Cases

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Inserting these values into the equations defined above allows you to determine the values for SETUP, STROBE, HOLD, and TA. For a read:

 

 

 

￿tEM_A ) tACC(m) ) tSU ) tEM_D￿

 

(0.27 ) 12 ) 5 ) 0.45)

 

R_SETUP ) R_STROBE w

 

 

 

 

 

 

 

 

 

* 1 w

 

 

 

 

 

 

* 1 w 0.78

tcyc

 

 

 

 

 

 

10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

tRC(m)

 

12

 

 

 

 

R_SETUP ) R_STROBE ) R_HOLD w

 

 

 

* 3

w ￿10￿*

3 w * 1.8

 

tcyc

R_HOLD w

￿tH * tEM_D * tOH(m) * tEM_A￿

* 1

(0 * 0.45 * 3 * 0.27)

1 w * 1.37

 

 

 

 

 

w

 

 

 

 

 

 

*

 

 

tcyc

 

 

10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

￿tEM_CS ) TCOD(m) ) tEM_D￿

 

 

(0.36 ) 7 ) 0.45)

 

 

 

 

 

TA w

 

 

* 1

w

 

 

 

 

* 1 w *0.22

 

 

 

10

 

 

 

 

 

tcyc

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Therefore if R_SETUP = 0, then R_STROBE = 0, R_HOLD = 0, and TA = 0.

For a write:

 

 

tWP(m)

8

￿* 1 w * 0.2

 

W_STROBE w

 

* 1 w ￿

 

 

tcyc

10

 

W_SETUP ) W_STROBE w max￿

￿tEM_A ) tAW(m) * tEM_WE￿

,

￿tEM_D ) tDS (m) * tEM_WE￿

￿* 1

 

tcyc

tcyc

wmax￿(0.36 ) 0 * 0.27) , (0.36 ) 0 * 0.45)￿* 1 w * 0.92

1010

W_HOLD w max￿

￿tEM_WE ) tWR(m) * tEM_A￿

,

￿tEM_WE ) tDH(m) * tEM_D￿

￿* 1

tcyc

 

tcyc

wmax￿(0.27 ) 9 * 0.36) , (0.45 ) 7 * 0.36)￿* 1 w * 0.1

1010

W_SETUP ) W_STROBE ) W_HOLD w tWC(m) * 3 w ￿12￿* 3 w * 1.8

tcyc10

Therefore, W_SETUP = 0, W_STROBE = 0, and W_HOLD = 0.

38

Asynchronous External Memory Interface (EMIF)

SPRUEQ7C –February 2010

 

 

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Texas Instruments TMS320DM646X DMSOC manual 27 12 5 Rsetup Rstrobe w