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ManualsBrandsRENESAS ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller LQFP 144 (20x20) 16-Bit 33 MHz I/O number 103
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Section 6 Bus Controller (BSC)
Rev. 3.00 Mar 17, 2006 page 156 of 926
REJ09B0283-0300
6.4.3 Memory Interfaces
The memory interfaces in this LSI comprise a basic bus interface that allows direct connection of
ROM, SRAM, and so on; a DRAM interface that allows direct connection of DRAM; a
synchronous DRAM interface
*
that allows direct connection of synchronous DRAM; and a burst
ROM interface that allows direct connection of burst ROM. The interface can be selected
independently for each area.
An area for which the basic bus interface is designated functions as normal space, an area for
which the DRAM interface is designated functions as DRAM space, an area for which the
synchronous DRAM interface is designated functions as continuous synchronous DRAM space,
and an area for which the burst ROM interface is designated functions as burst ROM space.
The initial state of each area is basic bus interface, 3-state access space. The initial bus width is
selected according to the operating mode.
Note: * The synchronous DRAM interface is not supported in the H8S/2678 Group.
Area 0: Area 0 includes on-chip ROM in expanded mode with on-chip ROM enabled and the
space excluding on-chip ROM is external address space, and in expanded mode with on-chip
ROM disabled, all of area 0 is external address space.
When area 0 external space is accessed, the CS0 signal can be output.
Either basic bus interface or burst ROM interface can be selected for area 0.
Area 1: In externally expanded mode, all of area 1 is external address space.
When area 1 external address space is accessed, the CS1 signal can be output.
Either basic bus interface or burst ROM interface can be selected for area 1.
Areas 2 to 5: In externally expanded mode, areas 2 to 5 are all external address space.
When area 2 to 5 external space is accessed, signals CS2 to CS5 can be output.
Basic bus interface, DRAM interface, or synchronous DRAM interface can be selected for areas 2
to 5. With the DRAM interface, signals CS2 to CS5 are used as RAS signals.
If areas 2 to 5 are designated as continuous DRAM space, large-capacity (e.g. 64-Mbit) DRAM
can be connected. In this case, the CS2 signal is used as the RAS signal for the continuous DRAM
space.