M38062M3-156FP MITSUBISHI [Mitsubishi Electric Semiconductor], M38062M3-156FP Datasheet - Page 30

• Manufacturer Part Number: M38062M3-156FP
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

Processor Modes
Single-chip mode, memory expansion mode, and microprocessor
mode can be selected by changing the contents of the processor
mode bits CM
memory expansion mode and microprocessor mode, memory can
be expanded externally through ports P0 to P3. In these modes,
ports P0 to P3 lose their I/O port functions and become bus pins.
Table 2.
Note: If CNV
Single-Chip Mode
Select this mode by resetting the microcomputer with CNV
nected to V
Memory Expansion Mode
Select this mode by setting the processor mode bits to “01” in soft-
ware with CNV
memory expansion while maintaining the validity of the internal
ROM. Internal ROM will take precedence over external memory if
addresses conflict.
Microprocessor Mode
Select this mode by resetting the microcomputer with CNV
nected to V
software with CNV
the internal ROM is no longer valid and external memory must be
used.
30
Port P0
Port P1
Port P2
Port P3
Port Name
single-chip mode after a reset, so this pin cannot be used
as the RESET
Functions of ports in memory expansion mode and
microprocessor mode
SS
CC
SS
_________
.
, or by setting the processor mode bits to “10” in
0
SS
is connected to V
and CM
connected to V
SS
OUT
Outputs low-order byte of address.
Outputs high-order byte of address.
Operates as I/O pins for data D
(including instruction codes).
P3
(except that the port latch cannot be read).
P3
P3
P3
P3
P3
___
RD output pin.
connected to V
0
2
3
4
5
6
1
output pin.
is the ONW input pin.
is the RESET
is the
is the SYNC output pin.
and P3
is the WR output pin, and P3
(bits 0 and 1 of address 003B
_____
_________
___
1
output pin.
SS
SS
function only as output pins
. This mode enables external
, the microcomputer goes to
SS
Function
OUT
. In microprocessor mode,
output pin. (Note)
7
to D
7
SS
SS
is the
0
16
con-
con-
). In
Fig. 28 Memory maps in various processor modes
Fig. 29 Structure of CPU mode register
0000
0008
0040
YYYY
FFFF
0440
b7
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
16
16
16
Memory expansion mode
16
16
16
:
The shaded areas are external memory areas.
YYYY
Internal RAM
reserved area
Internal ROM
SFR area
MITSUBISHI MICROCOMPUTERS
16
b0
is the start address of internal ROM.
CPU mode register
(CPUM : address 003B
b1 b0
Processor mode bits
0 0 : Single-chip mode
0 1 : Memory expansion mode
1 0 : Microprocessor mode
1 1 : Not available
Stack page selection bit
Not used (return “0” when read)
0 : 0 page
1 : 1 page
0000
0008
0040
FFFF
0440
3806 Group
16
16
16
16
16
Microprocessor mode
Internal RAM
reserved area
SFR area
16
)