Renesas 7700 FAMILY, User Manual

Page: 378 / 540

APPLICATIONS
7751 Group User’s Manual
17–13
17.1 Memory expansion
Fig. 17.1.9 Example of using Ready function (at 3
φ
access in low–speed running)
M37751
1D
1T
1Q
RDY
E
AC32
2D
2T
2Q
CLR
AC04
AC04
AC74
E
CS
2
1Q (AC74)
RDY
2Q (AC74)
B
A
t
c
t
d
(E-
φ
1
)
A
8
–A
23
(D
0
–D
15
)
A
0
–A
7
1
CS
1
Address bus
Data bus
Address
latch circuit
Address
decode
circuit
CS
2
✽
1
✽
2
✽
3
✽
1 to
✽
3
(f(X
IN
) = 25 MHz, 40 ns).
2
✕
10
f(X
IN
)
–t
su
(RDY–
1
)
9
Ready function is available
only for areas accessed
by CS
2
.
Use the elements of which sum of
propagation delay time is within
Circuit condition: f(X
IN
)
≤
25 MHz, 3 access in low–speed running
t
su(RDY-
1
)
t
su(RDY-
1
)
Sum of propagation delay time for AC32 , AC74,
and AC04(max. : 26 ns)
Ready request is accepted at the RDY pin input level judgment timing A .
Ready state release request is accepted at the RDY pin input level judgment timing B .
: E ( “L” level) stop by Ready function.
1
1
1