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M16C/6N5 Group
Bus
During memory expansion or microprocessor mode, some pins serve as the bus control pins to perform
data input/output to and from external devices. These bus control pins include A
_______ _____
________ ______
CS
, RD, WRL/WR, WRH/BHE, ALE, RDY, HOLD, HLDA and BCLK.
3
Bus Mode
The bus mode, either multiplexed or separate, can be selected using the PM05 to PM04 bits in the PM0
register.
Separate Bus
In this bus mode, data and address are separate.
Multiplexed Bus
In this bus mode, data and address are multiplexed.
• When the input level on BYTE pin is high (8-bit data bus)
D
to D
and A
0
7
• When the input level on BYTE pin is low (16-bit data bus)
D
to D
and A
0
7
External buses connecting to a multiplexed bus are allocated to only the even addresses of the
microcomputer. Odd addresses cannot be accessed.
Rev.1.00
2003.05.30
page 31
________ ________
________ __________
to A
are multiplexed.
0
7
to A
are multiplexed. D
1
8
_________
to D
are not multiplexed. Do not use D
8
15
Bus
_______
to A
, D
to D
, CS
to
0
19
0
15
0
to D
.
8
15
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