Datasheet

Section 23 ROM (H8S/2148 F-ZTAT A-Mask Version, H8S/2147 F-ZTAT A-Mask Version, H8S/2144 F-ZTAT A-Mask Version)
Rev. 4.00 Sep 27, 2006 page 685 of 1130
REJ09B0327-0400
Section 23 ROM
(H8S/2148 F-ZTAT A-Mask Version,
H8S/2147 F-ZTAT A-Mask Version,
H8S/2144 F-ZTAT A-Mask Version)
23.1 Overview
H8S/2148 F-ZTAT A-mask version and H8S/2144 F-ZTAT A-mask version have 128 kbytes, and
H8S/2147 F-ZTAT A-mask version has 64 kbytes of on-chip flash memory. The flash memory 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 flash memory versions of this group can be erased and programmed on-board as well as with
a general-purpose PROM programmer.
23.1.1 Block Diagram
Figure 23.1 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 23.1 ROM Block Diagram
(A-mask versions of the H8S/2148 F-ZTAT and H8S/2144 F-ZTAT)