HD6475328-CP10 Datasheet, PDF (44/459 Pages) Hitachi Semiconductor – original Hitachi CMOS microcomputer unit (MCU)

2.2 Mode Descriptions
The five MCU modes are described below. For further information on the I/O pin functions in
each mode, see section 9, “I/O Ports.”
Mode 1 (Expanded Minimum Mode): Mode 1 supports a maximum 64K-byte address space
which does not include any on-chip ROM. Ports 1 to 5 are used for bus lines and bus control
signals as follows:
Control signals: Ports 1* and 2
Data bus:
Port 3
Address bus: Ports 4 and 5
* The functions of individual pins of port 1 are software-selectable.
Mode 2 (Expanded Minimum Mode): Mode 2 supports a maximum 64K-byte address space of
which the first 32K bytes are in on-chip ROM. Ports 1 to 5 are used for bus lines and bus control
signals as follows:
Control signals: Ports 1* and 2
Data bus:
Port 3
Address bus: Ports 4 and 5*
* The functions of individual pins in ports 1 and 5 are software-selectable.
Note: In mode 2, port 5 is initially a general-purpose input port. Software must change it to
output before using it for the address bus. See section 9.6, “Port 5” for details. The following
instruction makes all pins of port 5 into output pins:
MOV.B #H'FF, @H'FF88*
* H'xx or H'xxxx express the hexadecimal number.
Mode 3 (Expanded Maximum Mode): Mode 3 supports a maximum 1M-byte address space
which does not include any on-chip ROM. Ports 1 to 6 are used for bus lines and bus control
signals as follows:
Control signals: Ports 1* and 2
Data bus:
Port 3
Address bus: Ports 4, 5, and 6
* The functions of individual pins of port 1 are software-selectable.
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