Instruction Fetch; Address Space; Figure 2.8 Memory Map - Renesas H8SX/1520 Series Hardware Manual

2.3

Instruction Fetch

The H8SX CPU has two modes for instruction fetch: 16-bit and 32-bit modes. It is recommended
that the mode be set according to the bus width of the memory in which a program is stored. The
instruction-fetch mode setting does not affect operation other than instruction fetch such as data
accesses.
Note: In the H8SX/1520 Group, an instruction is fetched in 32-bit mode.
2.4

Address Space

Figure 2.8 shows a memory map of the H8SX CPU. The address space differs depending on the
CPU operating mode.
Normal mode
H'0000
H'FFFF
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Middle mode
H'000000
H'007FFF
Program area
Data area
(64 kbytes)
H'FF8000
H'FFFFFF

Figure 2.8 Memory Map

Advanced mode
H'00000000
Program area
(16 Mbytes)
Data area
(64 kbytes)
H'00FFFFFF
H'FFFFFFFF
Rev. 3.00 Mar. 14, 2006 Page 27 of 804
Section 2 CPU
Maximum mode
H'00000000
Program area
(16 Mbytes)
Data area
(4 Gbytes)
H'FFFFFFFF
REJ09B0104-0300
Program area
Data area
(4 Gbytes)