Operating Mode Descriptions; Mode 1; Mode 2; Mode 3 - Hitachi H8/3006 Hardware Manual

3.4

Operating Mode Descriptions

3.4.1

Mode 1

A maximum 1-Mbyte address space can be accessed. The initial bus mode after a reset is 8 bits,
with 8-bit access to all areas. If at least one area is designated for 16-bit access in ABWCR, the
bus mode switches to 16 bits.
3.4.2

Mode 2

A maximum 1-Mbyte address space can be accessed. The initial bus mode after a reset is 16 bits,
with 16-bit access to all areas. If all areas are designated for 8-bit access in ABWCR, the bus
mode switches to 8 bits.
3.4.3

Mode 3

Part of port A function as address pins A
address space. The initial bus mode after a reset is 8 bits, with 8-bit access to all areas. If at least
one area is designated for 16-bit access in ABWCR, the bus mode switches to 16 bits. A
are valid when 0 is written in bits 7 to 5 of the bus release control register (BRCR). (In this mode
A is always used for address output.)
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3.4.4

Mode 4

Part of port A function as address pins A
address space. The initial bus mode after a reset is 16 bits, with 16-bit access to all areas. If all
areas are designated for 8-bit access in ABWCR, the bus mode switches to 8 bits. A
valid when 0 is written in bits 7 to 5 of BRCR. (In this mode A
output.)
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to A , permitting access to a maximum 16-Mbyte
23 20
to A , permitting access to a maximum 16-Mbyte
23 20
23
is always used for address
20
to A
23 21
to A are
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