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ADSP-21367/ADSP-21368/ADSP-21369
Rev. D
|
Page 29 of 56
|
November 2008
Memory Write
Use these specifications for asynchronous interfacing to memo-
ries. These specifications apply when the processors are the bus
masters, accessing external memory space in asynchronous
access mode. Note that timing for ACK, DATA, RD, WR, and
strobe timing parameters only applies to asynchronous access
mode.
Table 26. Memory Write
Parameter
Min
Max
Unit
Timing Requirements
t
DAAK
ACK Delay from Address, Selects
1, 2
t
SDCLK
– 9.7 + W
ns
t
DSAK
ACK Delay from WR Low
1, 3
W – 4.9
ns
Switching Characteristics
t
DAWH
Address, Selects to WR Deasserted
t
SDCLK
– 3.1+ W
ns
t
DAWL
Address, Selects to WR Low
t
SDCLK
– 2.7
ns
t
WW
WR Pulse Width
W – 1.3
ns
t
DDWH
Data Setup Before WR High
t
SDCLK
– 3.0+ W
ns
t
DWHA
Address Hold After WR Deasserted
H + 0.15
ns
t
DWHD
Data Hold After WR Deasserted
H + 0.02
ns
t
WWR
WR High to WR, RD Low
t
SDCLK
– 1.5+ H
ns
t
DDWR
Data Disable Before RD Low
2t
SDCLK
– 4.11
ns
t
WDE
WR Low to Data Enabled
t
SDCLK
– 3.5
ns
W = (number of wait states specified in AMICTLx register) × t
SDCLK
.
H = (number of hold cycles specified in AMICTLx register) × t
SDCLK
.
1
ACK delay/setup: System must meet t
DAAK
, or t
DSAK
, for deassertion of ACK (low). For asynchronous assertion of ACK (high), user must meet t
DAAK
or t
DSAK
.
2
The falling edge of MSx is referenced.
3
Note that timing for ACK, DATA, RD, WR, and strobe timing parameters only applies to asynchronous access mode.
Figure 19. Memory Write
ACK
DATA
t
DAWL
t
WW
t
DAAK
t
WWR
t
WDE
t
DDWR
t
DWHA
t
DAWH
t
D
S
AK
t
DDWH
t
DWHD
ADDRE
SS
MSx
WR
RD