M30622M4 MITSUBISHI [Mitsubishi Electric Semiconductor], M30622M4 Datasheet - Page 33

• Manufacturer Part Number: M30622M4
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

Bus Control
Bus Control
Table 1.12.1. External areas specified by the chip select signals
Note :Be sure to set bit 3 (PM13) of processor mode register 1 to “0”.
(A product having an internal RAM equal to or less than 15K bytes and a ROM equal to or less than 192K bytes)(Note)
The following explains the signals required for accessing external devices and software waits. The signals
required for accessing the external devices are valid when the processor mode is set to memory expansion
mode and microprocessor mode. The software waits are valid in all processor modes.
expansion mode
Memory space
Normal mode
(PM15,14=0,0)
Expansion
mode 1
(PM15,14=1,0)
Expansion
mode 2
(PM15,14=1,1)
(1) Address bus/data bus
(2) Chip select signal
The address bus consists of the 20 pins A
The data bus consists of the pins for data I/O. When the BYTE pin is “H”, the 8 ports D
as the data bus. When BYTE is “L”, the 16 ports D
When a change is made from single-chip mode to memory expansion mode, the value of the address
bus is undefined until external memory is accessed.
The chip select signal is output using the same pins as P4
register (address 0008
select control register is valid in memory expansion mode and microprocessor mode. In single-chip
mode, P4
register.
In microprocessor mode, only CS0 outputs the chip select signal after the reset state has been can-
celled. CS1 to CS3 function as input ports. Figure 1.12.1 shows the chip select control register.
The chip select signal can be used to split the external area into as many as four blocks. Tables 1.12.1
and 1.12.2 show the external memory areas specified using the chip select signal.
_______
4
to P4
Memory expansion mode
Memory expansion mode
Microprocessor mode
Microprocessor mode
Memory expansion mode
Microprocessor mode
_______
7
Processor mode
function as programmable I/O ports regardless of the value in the chip select control
16
) set each pin to function as a port or to output the chip select signal. The chip
_______
(512K bytes X 7 +
(512K bytes X 8)
(1008K bytes)
(640K bytes)
(832K bytes)
(816K bytes)
256K bytes)
40000
30000
30000
04000
04000
40000
CFFFF
CFFFF
BFFFF
FFFFF
FFFFF
FFFFF
0
CS0
to A
16
16
16
16
16
16
16
16
16
16
16
16
to
to
to
to
to
to
19
for accessing the 1M bytes of address space.
0
to D
(32K bytes)
(96K bytes)
15
28000
28000
4
2FFFF
3FFFF
to P4
function as the data bus.
CS1
Chip select signal
16
16
16
16
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
to
to
7
. Bits 0 to 3 of the chip select control
(128K bytes)
08000
27FFF
CS2
16
16
to
Mitsubishi microcomputers
M16C / 62 Group
0
to D
(16K bytes)
04000
07FFF
CS3
7
function
16
16
to
33