Mitsubishi microcomputers
M16C / 61 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Processor Mode
20
Figure 1.8.1. Processor mode register 0 and 1
Processor mode register 0 (Note 1)
Symbol
PM0
Address
0004
16
When reset
00
16
(Note 2)
Bit name
Function
Bit symbol
b7
b6
b5
b4
b3
b2
b1
b0
0 0: Single-chip mode
0 1: Memory expansion mode
1 0: Inhibited
1 1: Microprocessor mode
b1 b0
PM03
PM01
PM00
Processor mode bit
PM02
R/W mode select bit
0 : RD,BHE,WR
1 : RD,WRH,WRL
Software reset bit
The device is reset when this bit is set
to “1”. The value of this bit is “0” when
read.
PM04
0 0 : Multiplexed bus is not used
0 1 : Allocated to CS2 space
1 0 : Allocated to CS1 space
1 1 : Allocated to entire space (Note4)
b5 b4
Multiplexed bus space
select bit
PM05
PM06
PM07
Port P4
0
to P4
3
function
select bit (Note 3)
0 : Address output
1 : Port function
(Address is not output)
BCLK output disable bit
0 : BCLK is output
1 : BCLK is not output
(Pin is left floating)
Note 1: Set bit 1 of the protect register (address 000A
16
) to “1” when writing new
values to this register.
Note 2: If the V
CC
voltage is applied to the CNV
SS
, the value of this register when
reset is 03
16.
(PM00 and PM01 both are set to “1”.)
Note 3: Valid in microprocessor and memory expansion modes.
Note 4: 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.
Processor mode register 1 (Note 1)
Symbol
PM1
Address
0005
16
When reset
00XXXXX0
2
Bit name
Function
Bit symbol
W
R
b7
b6
b5
0
b4
0
b3
0
b2
b1
b0
0
Nothing is assigned.
In an attempt to write to these bits, write “0”. The value, if read, turns out to be
indeterminate.
PM16
External memory area
expansion bit (Note 2)
0 : Do not expand
1 : Expand
Reserved bit
Must always be set to “0”
Note 1: Set bit 1 of the protect register (address 000A
16
) to “1” when writing
new values to this register.
Note 2: When this bit is set to “1” in memory expansion mode, M30612M4A/E4
provides the means of using part of internal reserved area as an external
area. Set this bit to “0” except M30612M4A/E4. Set this bit to “0” in single
chip mode.
PM17
Wait bit
0 : No wait state
1 : Wait state inserted
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
AA
Reserved bit
Must always be set to “0”
AA