Datasheet

Section 22 ROM (Mask ROM Version, H8S/2148 F-ZTAT, H8S/2147N F-ZTAT, H8S/2144 F-ZTAT, and H8S/2142 F-ZTAT)
Rev. 4.00 Sep 27, 2006 page 639 of 1130
REJ09B0327-0400
Section 22 ROM
(Mask ROM Version, H8S/2148 F-ZTAT,
H8S/2147N F-ZTAT, H8S/2144 F-ZTAT,
and H8S/2142 F-ZTAT)
22.1 Overview
The H8S/2148 and H8S/2144 have 128 kbytes of on-chip ROM (flash memory or mask ROM),
the H8S/2143 has 96 kbytes, the H8S/2147, H8S/2147N, and H8S/2142 have 64 kbytes. The
ROM is connected to the CPU by a 16-bit data bus. The CPU 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 flash memory versions of the H8S/2148, H8S/2147N, H8S/2144, and H8S/2142 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.
H'000000
H'000002
H'01FFFE
H'000001
H'000003
H'01FFFF
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
Figure 22.1 ROM Block Diagram (H8S/2148, H8S/2144)