M306V0ME Mitsubishi, M306V0ME Datasheet - Page 29

• Manufacturer Part Number: M306V0ME
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER and ON-SCREEN DISPLAY CONTROLLER
• Manufacturer: Mitsubishi

Rev. 1.0
Table 2.4.3 External areas specified by the chip select signals
2.4.4 Bus Control
The following explains the signals required for accessing external devices and software waits. The sig-
nals 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.
(1) Address bus/data bus
(2) Chip select signal
Chip select
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 2.4.4 shows the chip select control register.
The chip select signal can be used to split the external area into as many as four blocks. Table 2.4.4
shows the external memory areas specified using the chip select signal.
CS0
CS1
CS2
CS3
_______
4
to P4
_______
30000
28000
08000
04000
7
Memory expansion mode
function as programmable I/O ports regardless of the value in the chip select control
16
16
16
16
16
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
to 8FFFF
to 2FFFF
to 27FFF
to 07FFF
) set each pin to function as a port or to output the chip select signal. The chip
_______
16
16
16
16
(384K)
(32K)
(128K)
(16K)
0
to A
Specified address range
30000
28000
08000
04000
19
for accessing the 1M bytes of address space.
0
16
16
16
16
to D
to 8FFFF
to 2FFFF
to 27FFF
to 07FFF
15
4
to P4
function as the data bus.
16
16
16
16
and ON-SCREEN DISPLAY CONTROLLER
Microprocessor mode
7
(128K)
(16K)
(384K), B0000
(32K)
. Bits 0 to 3 of the chip select control
MITSUBISHI MICROCOMPUTERS
M306V0ME-XXXFP
16
M306V0EEFP
to FFFFF
0
to D
16
7
(320K)
function
29