HD6432345 Datasheet, PDF (549/907 Pages) Hitachi Semiconductor – H8S/2345 F-ZTAT Hardware Manual

Section 17 ROM
17.1 Overview
The H8S/2345 has 128 kbytes of on-chip ROM (flash memory, PROM, or mask ROM); the
H8S/2344 has 96 kbytes of on-chip ROM (mask ROM); the H8S/2343 has 64 kbytes of on-chip
ROM (mask ROM); and the H8S/2341 has 32 kbytes of on-chip ROM (mask ROM). The ROM is
connected to the H8S/2000 CPU by a 16-bit data bus. The CPU accesses both byte data and word
data in one state, making possible rapid instruction fetches and high-speed processing.
The on-chip ROM is enabled or disabled by setting the mode pins (MD₂, MD₁, and MD₀) and bit
EAE in BCRL.
The flash memory versions of the H8S/2345 Series can be erased and programmed on-board as
well as with a PROM programmer.
The PROM version of the H8S/2345 Series can be programmed with a PROM programmer, by
setting PROM mode.
17.1.1 Block Diagram
Figure 17.1 shows a block diagram of the on-chip ROM.
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
H'000000
H'000002
H'000001
H'000003
H'01FFFE
H'01FFFF
Figure 17.1 Block Diagram of ROM (H8S/2345)
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