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Section 6 Bus Controller
Areas 2 to 5: In external expansion mode, areas 2 to 5 are entirely external space.
When area 2 to 5 external space is accessed, signals CS
to CS
can be output.
2
5
Basic bus interface or DRAM interface can be selected for areas 2 to 5. With the DRAM interface,
signals CS
to CS
are used as RAS signals.
2
5
The size of areas 2 to 5 is 128 kbytes in modes 1 and 2, and 2 Mbytes in modes 3, 4, and 5.
Area 7: Area 7 includes the on-chip RAM and registers. In external expansion mode, the space
excluding the on-chip RAM and registers is external space. The on-chip RAM is enabled when the
RAME bit in the system control register (SYSCR) is set to 1; when the RAME bit is cleared to 0,
the on-chip RAM is disabled and the corresponding space becomes external space.
When area 7 external space is accessed, the CS
signal can be output.
7
Only the basic bus interface can be used for the area 7 memory interface.
The size of area 7 is 128 kbytes in modes 1 and 2, and 2 Mbytes in modes 3, 4, and 5.
Rev. 4.00 Jan 26, 2006 page 155 of 938
REJ09B0276-0400
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