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Mitsubishi microcomputers
M16C / 62T Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Bus Settings
Table 1.11.2. Pin functions for each processor mode
I/O port
Processor mode
Memory expansion / microprocessor modes
(separate bus)
“01”, “10”
“00”
“11” (Note 2)
8 bits “H”
16 bits “L”
8 bits “H”
P00 to P07
P10 to P17
P20
P21 to P27
P30
P31 to P37
Port P40 to P43
P40 to P43
function select bit = 1
Port P40 to P43
P40 to P43
function select bit = 0
P50 to P53
P54
P55
P56
P57
P44 to P47
Data bus
I/O port
Data bus
I/O port
Data bus
I/O port
Address bus
I/O port
Address bus
I/O port
Address bus
A8/D7
I/O port
Address bus
I/O port
Address bus
I/O port
ALE
Single-chip
mode
multiplexed bus
for the entire space
Memory
expansion mode
(Note 1)
Address bus
/data bus
Address bus
/data bus
Address bus/
data bus (Note 3)
Address bus/
data bus (Note 3)
Address bus/
data bus (Note 3)
Address bus/
data bus (Note 3)
Either CS1 or CS2 is for multiplexed bus
and others are for separate bus
Multiplexed bus
space select bit
Data bus width
BYTE pin level
RDY
HOLD
HLDA
ALE
RDY
HOLD
HLDA
ALE
RDY
HOLD
HLDA
ALE
RDY
HOLD
HLDA
ALE
RDY
HOLD
HLDA
CS (chip select) or programmable I/O port
(For details, refer to “Bus control”.)
Outputs RD, WRL, WRH, and BCLK or RD, BHE, WR, and BCLK
(For details, refer to “Bus control”.)
Note 1: In M30623(80-pin package), set the data bus width to 8 bits by any of the following operations, to transfer the
microcomputer to memory expansion mode correctly.
At reset, input “H” to the CNVSS (BYTE) pin to start the program in microprocessor mode. Then, set the
processor mode bit to memory expansion mode.
At reset, input “L” to the CNVSS (BYTE) pin to start the program in single-chip mode, and input “H” to this pin.
Then, set the processor mode bit to memory expansion mode.
Note 2: If the entire space is of multiplexed bus in memory expansion mode, choose an 8-bit width. The processor
operates using the separate bus after reset is revoked, so the entire space multiplexed bus cannot be chosen
in microprocessor mode.
The higher-order address becomes a port if the entire space multiplexed bus is chosen, so only 256 bytes can
be used in each chip select.
Note 3: Address bus when in separate bus mode.
Note 4: In M30623(80-pin package), P1, P44 to P47 have no corresponding external pin.
Note 5: M16C/62T group is not guaranteed to operate in memory expansion and microprocessor modes.