6.3.6 Interconnections with Memory (Example)
For each area, the bus controller can select two- or three-state access and an 8- or 16-bit data bus
width. In three-state-access areas, wait states can be inserted in a variety of modes, simplifying the
connection of both high-speed and low-speed devices.
Figure 6-18 shows an example of interconnections between the H8/3048 Series and memory.
Figure 6-17 shows a memory map for this example.
A 256-kword
×
16-bit EPROM is connected to area 0. This device is accessed in three states via a
16-bit bus.
Two 32-kword
×
8-bit SRAM devices (SRAM1 and SRAM2) are connected to area 1. These
devices are accessed in two states via a 16-bit bus.
One 32-kword
×
8-bit SRAM (SRAM3) is connected to area 2. This device is accessed via an
8-bit bus, using three-state access with an additional wait state inserted in pin auto-wait mode.
Figure 6-17 Memory Map (Example)
H'000000
H'07FFFF
H'1FFFFF
H'200000
H'20FFFF
H'210000
H'3FFFFF
H'400000
H'FFFFFF
On-chip RAM
On-chip registers
EPROM
Not used
SRAM 1, 2
Not used
SRAM 3
Area 0
16-bit, three-state-access area
Area 1
16-bit, two-state-access area
Area 2
8-bit, three-state-access area
(one auto-wait state)
H'407FFF
H'5FFFFF
Not used
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