HD64F2149 Datasheet, PDF (691/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

Section 22 ROM
22.1 Overview
The H8S/2169 or H8S/2149 has 64 kbytes of on-chip ROM (flash memory). The ROM is
connected to the bus master by a 16-bit data bus. The bus master accesses both byte and word data
in one state, enabling faster instruction fetches and higher processing speed.
The mode pins (MD1 and MD0) and the EXPE bit in MDCR can be set to enable or disable the
on-chip ROM.
The chip can be erased and programmed on-board as well as with a general-purpose PROM
programmer.
22.1.1 Block Diagram
Figure 22.1 shows a block diagram of the ROM.
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
H'000000
H'000002
H'000001
H'000003
H'00FFFE
H'00FFFF
Figure 22.1 ROM Block Diagram
657