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8- 12
MC68306 USER'S MANUAL
MOTOROLA
8.10 BUS OPERATION—DRAM ACCESSES AC TIMING
SPECIFICATIONS
(The electrical specifications in this document are preliminary. See Figures 8-8–8-11)
16.67 MHz
0-Wait
1-Wait
Num.
Characteristic
Min
Max
Min
Max
Unit
71
CLKOUT High to
RAS≈
Asserted (0 Wait State Operation)
0
30
–
–
ns
71A
AS
Asserted to
RAS≈
Asserted (0 Wait State Operation)
0
10
–
–
ns
72
CLKOUT Low to
RAS≈
Asserted (1 Wait State Operation)
–
–
0
25
ns
73
CLKOUT Low to Row
Address Valid
0
30
0
30
ns
74
Row Address Valid to
RAS≈
Asserted
15
–
30
–
ns
75
RAS≈
Asserted to Row Address Invalid
20
–
40
–
ns
76
CLKOUT High to Row Address Invalid (0 Wait State Operation)
0
–
–
–
ns
77
CLKOUT Low to Row Address Invalid (1 Wait State Operation)
–
–
0
–
ns
78
RAS≈
Width Asserted (Non-Page Mode)
120
180
150
210
ns
79
RAS≈
Width Asserted (Page Mode)
480
540
510
570
ns
80
RAS≈
Width Negated (Back to Back Cycles)
60
–
90
–
ns
81
RAS≈
Asserted to
CAS≈
Asserted
45
–
60
–
ns
82
CLKOUT High to Column Address
Valid
(0 Wait State Operation)
0
30
–
–
ns
83
CLKOUT Low to Column Address
Valid
(1 Wait State Operation)
–
–
0
30
ns
84
CLKOUT Low to
CAS≈
Asserted (0 Wait State Operation)
0
20
–
–
ns
85
CLKOUT High to
CAS≈
Asserted (1 Wait State Operation)
–
–
0
20
ns
86
Column Address Valid to
CAS≈
Asserted
20
–
20
–
ns
87
CAS≈
Asserted to Column Address Invalid
75
–
100
–
ns
88
CAS≈
Width Asserted
60
90
90
120
ns
89
CLKOUT Low to
RAS≈
/
CAS≈
Negated
0
30
0
30
ns
89A
AS
Negated to
RAS≈
/
CAS≈
Negated
0
10
0
10
ns
90
CAS≈
Width Negated (Back to Back Cycles)
150
–
180
–
ns
91
CAS≈
Width Negated (Page Mode
2
)
240
300
240
300
ns
92
UDS/LDS
Asserted to
CAS≈
Asserted
1
(Page Mode
2
)
0
10
0
10
ns
93
DRAMW
Low to
CAS≈
Asserted (Write)
30
–
60
–
ns
94
Data Out Valid to
CAS≈
Asserted (Write)
15
–
45
–
ns
95
CLKOUT Low to
CAS≈
Asserted (Refresh Cycle)
0
20
0
20
ns
96
CLKOUT High to
CAS≈
Negated (Refresh Cycle)
0
20
0
20
ns
97
CAS≈
Width Asserted (Refresh Cycle)
80
120
140
180
ns
98
CAS≈
Asserted to
RAS≈
Asserted (Refresh Cycle)
20
60
20
60
ns
99
CLKOUT High to
RAS≈
Asserted (Refresh Cycle)
0
30
0
30
ns
100
CLKOUT Low to
RAS≈
Negated (Refresh Cycle)
0
25
0
25
ns
101
RAS≈
Width Asserted (Refresh Cycle)
80
120
140
180
ns
102
DRAMW
High to
RAS≈
Asserted (Refresh Cycle)
20
60
20
60
ns
103
DRAMW
High Hold After
RAS≈
Asserted (Refresh Cycle)
20
–
20
–
ns
NOTES:
1. On write portion of TAS,
CAS
assertion is gated by
UDS/LDS
(not CLKOUT as in all other operation).
2. Page mode is used on Read-Modify-Write (TAS instruction) cycles only.