M37733MHBXXXFP Datasheet, PDF (10/89 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

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MITSUBISHI MICROCOMPUTERS
M37733MHBXXXFP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
The bus interface unit operates using one of the waveforms (1) to
(10) shown in Figure 5. The standard waveforms are (1) and (2).
The ALE signal is used to latch only the address signal from the
multiplexed signal containing data and address.
The E signal becomes “L” when the bus interface unit reads an
instruction code or data from the memory or when it writes data to
the memory. Whether to perform read or write is controlled by the
R/W signal. When the R/W signal is “H”, read is performed; when “L”,
write is performed.
Waveform (1) in Figure 5 is used to access a single byte or two bytes
simultaneously. To read or write two bytes simultaneously, the first
address accessed must be even. Furthermore, when accessing an
external memory area in the memory expansion mode or the
microprocessor mode, set the bus width selection input pin (BYTE)
to “L” (external data bus has a width of 16 bits). The data bus in the
internal memory area is always treated as the 16-bit bus independent
of BYTE.
Internal clock φ
Port P2
(1)
E
ALE
Port P2
(2)
E
ALE
AD
Access time
A D A+1 D
Access time
Port P2
(3)
E
ALE
A
D
Access time
Port P2
(4)
E
ALE
Port P2
(5)
E
ALE
A
D
A +1
D
Access time
A
D ^A+1 D
Access time
Port P2
(6)
E
ALE
A D A+1 D
Access time
Fig. 5 Bus access timing
Internal clock φ
Port P2
(7)
E
ALE
Port P2
(8)
E
ALE
Port P2
(9)
E
ALE
Port P2
(10)
E
ALE
A : Address
D : Data
A
D
Access time
A
D
A+1
D
Access time
A
D
A+1 D
Access time
A D A+1
D
Access time
10