M37733MHBXXXFP Datasheet, PDF (51/89 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

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MITSUBISHI MICROCOMPUTERS
M37733MHBXXXFP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
• Wait bit
As shown in Figure 60, when the external memory area is accessed
with the wait bit (bit 2 of the processor mode register 0 at address
5E16) cleared to “0”, the access time can be extended compared with
no wait (the wait bit is “1”).
The access time is extended in two ways and this is selected with the
wait selection bit (bit 0 of the processor mode register 1 at address
5F16).
When this bit is “1”, the access time is 1.5 times compared to that for
no wait. When this bit is “0”, the access time is twice compared to
that for no wait.
At reset, the wait bit and the wait selection bit are “0”.
The accessing of internal memory area is always performed in the
no wait mode regardless of the wait bit.
The processor modes are described below.
Memory expansion Microprocessor
mode
mode
0016
SFR
SFR
8016
Evaluation
chip mode
216
A16
C16
SFR
Internal clock
Port P2
Wait bit “1”
(No wait) ^E
ALE
Address Data Address Data
Port P2
Wait bit “0”
(Wait 1) ^E
ALE
Access time
Address Data Address Data
Port P2
Wait bit “0”
(Wait 0) ^E
ALE
Access time
Address
Data
Address
Access time
Fig. 60 Relationship between wait bit, wait selection bit, and access time
RAM
RAM
RAM
FFF16
100016
ROM
1FFFF16
FFFFFF16
The shaded area is the external memory area.
Fig. 59 External memory area for each processor mode
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