
50
4431E–8051–04/06
AT/TS8xC54/8X2
19.5.4
External Data Memory Characteristics
Table 19-8.
Symbol Description
Table 19-9.
AC Parameters for a Fix Clock
Symbol
Parameter
TRLRH
RD Pulse Width
TWLWH
WR Pulse Width
T
RLDV
RD to Valid Data In
TRHDX
Data Hold After RD
TRHDZ
Data Float After RD
T
LLDV
ALE to Valid Data In
TAVDV
Address to Valid Data In
TLLWL
ALE to WR or RD
T
AVWL
Address to WR or RD
TQVWX
Data Valid to WR Transition
TQVWH
Data set-up to WR High
T
WHQX
Data Hold After WR
TRLAZ
RD Low to Address Float
TWHLH
RD or WR High to ALE high
Speed
-M
40 MHz
-V
X2 mode
30 MHz
60 MHz equiv.
-V
standard mode 40
MHz
-L
X2 mode
20 MHz
40 MHz equiv.
-L
standard mode
30 MHz
Units
Symbol
Min
Max
Min
Max
Min
Max
Min
Max
Min
Max
TRLRH
130
85
135
125
175
ns
TWLWH
130
85
135
125
175
ns
T
RLDV
100
60
102
95
137
ns
T
RHDX
0000
0
ns
TRHDZ
30
18
35
25
42
ns
TLLDV
160
98
165
155
222
ns
TAVDV
165
100
175
160
235
ns
T
LLWL
50
100
3070
559545
105
70
130
ns
T
AVWL
75
47
80
70
103
ns
TQVWX
10
7
15
5
13
ns
TQVWH
160
107
165
155
213
ns
TWHQX
15
9
171018
ns
T
RLAZ
0
0000
ns
T
WHLH
10
40727
15
355
45
13
53
ns