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HD6413007F20 Datasheet, PDF (94/798 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series
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3. MCU Operating Modes
3.4.3 Mode 3
Part of port A function as address pins A23 to A20, permitting access to a maximum 16-Mbyte
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. A23 to A21
are valid when 0 is written in bits 7 to 5 of the bus release control register (BRCR). (In this mode
A20 is always used for address output.)
3.4.4 Mode 4
Part of port A function as address pins A23 to A20, permitting access to a maximum 16-Mbyte
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. A23 to A21 are
valid when 0 is written in bits 7 to 5 of BRCR. (In this mode A20 is always used for address
output.)
3.5 Pin Functions in Each Operating Mode
The pin functions of port 4 and port A vary depending on the operating mode. Table 3.3 indicates
their functions in each operating mode.
Table 3.3 Pin Functions in Each Mode
Port
Mode 1
Mode 2
Mode 3
Mode 4
Port 4
P47 to P40*1
D7 to D0*1
P47 to P40*1
D7 to D0*1
Port A
PA7 to PA4
PA7 to PA4
PA6 to PA4, A20*2
PA6 to PA4, A20*2
Notes: 1. Initial state. The bus mode can be switched by settings in ABWCR. These pins function
as P47 to P40 in 8-bit bus mode, and as D7 to D0 in 16-bit bus mode.
2. Initial state. A20 is always an address output pin. PA6 to PA4 are switched over to A23 to
A21 output by writing 0 in bits 7 to 5 of BRCR.
Rev.5.00 Sep. 12, 2007 Page 64 of 764
REJ09B0396-0500
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