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3.3
Operating Mode Descriptions
This LSI has four operating modes, mode 4 to mode 7.
Modes 4 to 6 are extended modes in which external memory and external peripheral devices can
be accessed. In extended modes, each area can be used as 8-bit or 16-bit address space according
to the bus controller settings after program execution. In this case, if an area is specified as 16-bit
access space, 16-bit bus mode is employed for all areas; while if an area is specified as 8-bit access
space, 8-bit bus mode is employed for all areas.
In mode 7, external addresses cannot be used.
3.3.1
Mode 4
The CPU can access a 16-Mbyte address space in advanced mode. The on-chip ROM is disabled.
Pins P13 to P10, and ports A, B, and C function as an address bus, ports D and E function as a data
bus, and part of port F carries bus control signals.
Pins P13 to P11 function as input ports immediately after a reset. Pin 10 and ports A and B
function as address (A20 to A8) outputs immediately after a reset. Address (A23 to A21) output
can be enabled or disabled by bits AE3 to AE0 in the pin function control register (PFCR)
regardless of the corresponding data direction register (DDR) values. Pins for which address
output is disabled among pins P13 to P10 and in ports A and B become port outputs when the
corresponding DDR bits are set to 1.
Port C always has an address (A7 to A0) output function.
The initial bus mode after a reset is 16 bits, with 16-bit access to all areas. However, note that if 8-
bit access is designated by the bus controller for all areas, the bus mode switches to 8 bits.
3.3.2
Mode 5
The CPU can access a 16-Mbyte address space in advanced mode. The on-chip ROM is disabled.
Pins P13 to P10, and ports A, B, and C function as an address bus, ports D and E function as a data
bus, and part of port F carries bus control signals.
Pins P13 to P11 function as input ports immediately after a reset. Pin 10 and ports A and B
function as address (A20 to A8) outputs immediately after a reset. Address (A23 to A21) output
can be enabled or disabled by bits AE3 to AE0 in the pin function control register (PFCR)
regardless of the corresponding data direction register (DDR) values. Pins for which address
output is disabled among pins P13 to P10 and in ports A and B become port outputs when the
corresponding DDR bits are set to 1.
Rev. 3.0, 10/02, page 58 of 686
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