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Chapter 7
Bus and Memory Control (BCU, MEMC)
Preliminary User’s Manual U17566EE1V2UM00
7.7.1
Half word/word access with 8-bit bus or word access with 16-
bit bus
(1)
Read operation
Note that during on-page access, less data wait states are inserted than during
off-page access.
Figure 7-17
Reading page ROM
• Register settings:
• BCTm.BTk0 = 1 (connected external device is page ROM)
• ASC.ACk[1:0] = 00
B
(no address setup wait states inserted)
• DWCm.DWk[2:0] = 010
B
(two programmable data wait states for off-page
access inserted)
• PRC.PRW[2:0] = 001
B
(one programmable data wait state for on-page
access inserted)
• BCC.BCk[1:0] = 00
B
(no idle states inserted)
Note
1.
The circles indicate the sampling timing.
2.
The broken line indicates the high-impedance state (bus is not driven).
T1
Off-p
a
ge
a
ddre
ss
D
a
t
a
WAIT (inp
u
t)
D[15:0] (I/O)
D[7:0] (I/O)
WR (o
u
tp
u
t)
RD (o
u
tp
u
t)
C
S
k (o
u
tp
u
t)
A[2
3
:0] (o
u
tp
u
t)
BCLK
D
a
t
a
On-p
a
ge
a
ddre
ss
TO1
T2
TW
TO2
TW
TOW
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