Renesas F-ZTAT H8 Series, Hardware Manual

Page: 145 / 562

6. ROM
Rev.3.00 Jul. 19, 2007 page 119 of 532
REJ09B0397-0300
Section 6 ROM
6.1 Overview
The H8/3857 has 60 kbytes of on-chip flash memory or mask ROM, while the H8/3856 has 48
kbytes, and the H8/3855 40 kbytes, of on-chip mask ROM. The H8/3854 has 60 kbytes of on-chip
flash memory or 32 kbytes of on-chip mask ROM, while the H8/3853 has 24 kbytes, and the
H8/3852 16 kbytes, of on-chip mask ROM. Note that the H8/3854 flash memory and mask ROM
versions have different ROM sizes. The ROM is connected to the CPU by a 16-bit data bus,
allowing high-speed 2-state data access for both byte data and word data.
With the flash memory versions (H8/3857F, H8/3854F), programs can be written and erased and
programmed either with a general-purpose PROM programmer or on-board.
When carrying out program development using the H8/3854F with the intention of mask ROM
implementation, care must be taken with ROM and RAM sizes since the maximum sizes for the
mask ROM version are 32 kbytes of ROM and 1 kbyte of RAM.
6.1.1 Block Diagram
Figure 6.1 shows a block diagram of the on-chip ROM.
H'EDFE H'EDFF
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
Even-numbered
address
Odd-numbered
address
H'EDFE
H'0002
H'0000
H'0000
H'0002
H'0001
H'0003
On-chip ROM
Figure 6.1 ROM Block Diagram (60 kbytes)