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APPLICAT IONS
7751 Group User’s Manual
17–17
17.1 Memory expansion
Memory
EPROM
One-time PROM
Flash memory
SRAM
_
When using external memory that outputs data for more than t
pzx(E-P1Z/P2Z)
after rising of E
signal
Because the external memory outputs data for more than t
pzx(E-P1Z/P2Z)
after rising of the E signal,
there will be a possibility of the tail of data colliding with the head of address. In such a case,
examine the method described below:
G
Cut the tail of data output from the external memory by using, for example, a bus buffer.
G
Use the Mitsubishi’s memory chips that can be connected without a bus buffer.
Figures 17.1.13 to 17.1.20 show examples for how to use a bus buffer and the timing charts. Table
17.1.5 lists the memory chips that can be connected a without bus buffer. When using one of these
memory chips, the user can connect it to the user’s microcomputer without a bus buffer because
timing parameters t
DF
and t
dis(OE)
listed below are guaranteed. (However, the read signal must go
high within 10 ns after rising of E signal.)
Table 17.1.5 Memory chips that can be connected without bus buffer
Type description
M5M27C256AK-85, -10, -12, -15
M5M27C512AK-10, -12, -15
M5M27C100K-12. -15
M5M27C101K-12, -15
M5M27C102K-12, -15
M5M27C201K, JK-10, -12, -15
M5M27C202K, JK-10, -12, -15
M5M27C256AP, FP, VP, RV-12, -15
M5M27C512AP, FP-15
M5M27C100P-15
M5M27C101P, FP, J, VP, RV-15
M5M27C102P, FP, J, VP, RV-15
M5M27C201P, FP, J, VP, RV-12, -15
M5M27C202P, FP, J, VP, RV-12, -15
M5M28F101P, FP, J, VP, RV-10, -12, -15
M5M28F102FP, J, VP, RV-10, -12, -15
M5M5256CP, FP, KP, VP, RV-55LL, -55XL,
-70LL, -70XL, -85LL, -85XL, -10LL, -10XL
M5M5278CP, FP, J-20, -20L
t
DF
/t
dis(OE)
(Maximum)
15 ns
(when guaranteeing by
kit)
(Note)
8 ns
10 ns
6 ns
7 ns
8 ns
Conditions
f(X
IN
)
≤
20 MHz, at low–speed running
f(X
IN
)
≤
40 MHz, at high–speed running
f(X
IN
)
≤
25 MHz, at low–speed running
f(X
IN
)
≤
25 MHz, at low–speed running
f(X
IN
)
≤
40 MHz, at high–speed running
f(X
IN
)
≤
25 MHz, at low–speed running
M5M5278CP, FP, J-25, -25L
M5M5278DP, J-12
M5M5278DP, FP, J-15, -15L
M5M5278DP, FP, J-20, -20L
Note:
When the user want specifications of the memory chips listed above, add a comment “t
DF
/t
dis(OE)
15 ns
product, microcomputer and kit.”