Computer Hardware User Manual
R_SETUP ) R_STROBE w
ǒ
t
EM_A
) t
ACC
(m) ) t
SU
) t
EM_D
Ǔ
t
cyc
* 1 w
(
0.27 ) 12 ) 5 ) 0.45
)
10
* 1 w 0.78
R_SETUP ) R_STROBE ) R_HOLD w
t
RC
(m)
t
cyc
* 3 w
ǒ
12
10
Ǔ
* 3 w * 1.8
R_HOLD w
ǒ
t
H
* t
EM_D
* t
OH
(m) * t
EM_A
Ǔ
t
cyc
* 1 w
(
0 * 0.45 * 3 * 0.27
)
10
* 1 w * 1.37
TA w
ǒ
t
EM_CS
) T
COD
(m) ) t
EM_D
Ǔ
t
cyc
* 1 w
(
0.36 ) 7 ) 0.45
)
10
* 1 w *0.22
W_STROBE w
t
WP
(m)
t
cyc
* 1 w
ǒ
8
10
Ǔ
* 1 w * 0.2
W_SETUP ) W_STROBE w max
ǒ
ǒ
t
EM_A
) t
AW
(m) * t
EM_WE
Ǔ
t
cyc
,
ǒ
t
EM_D
) t
DS
(m) * t
EM_WE
Ǔ
t
cyc
Ǔ
* 1
w max
ǒ
(
0.36 ) 0 * 0.27
)
10
,
(
0.36 ) 0 * 0.45
)
10
Ǔ
* 1 w * 0.92
W_HOLD w max
ǒ
ǒ
t
EM_WE
) t
WR
(m) * t
EM_A
Ǔ
t
cyc
,
ǒ
t
EM_WE
) t
DH
(m) * t
EM_D
Ǔ
t
cyc
Ǔ
* 1
w max
ǒ
(
0.27 ) 9 * 0.36
)
10
,
(
0.45 ) 7 * 0.36
)
10
Ǔ
* 1 w * 0.1
W_SETUP ) W_STROBE ) W_HOLD w
t
WC
(m)
t
cyc
* 3 w
ǒ
12
10
Ǔ
* 3 w * 1.8
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:
Therefore if R_SETUP = 0, then R_STROBE = 0, R_HOLD = 0, and TA = 0.
For a write:
Therefore, W_SETUP = 0, W_STROBE = 0, and W_HOLD = 0.
38
Asynchronous External Memory Interface (EMIF) SPRUEQ7C–February 2010
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