Section 6 Rom; Overview; Block Diagram - Renesas H8 Series Hardware Manual

6.1

Overview

The H8/3644 has 32 kbytes of on-chip mask ROM, PROM or flash memory. The H8/3643 has 24
kbytes of mask ROM or flash memory. The H8/3642 has 16 kbytes of mask ROM or flash
memory. The H8/3641 has 12 kbytes of on-chip ROM. H8/3640 has 8 kbytes of ROM. The ROM
is connected to the CPU by a 16-bit data bus, allowing high-speed two-state access for both byte
data and word data.
In the PROM version (H8/3644 ZTAT) and flash memory versions (H8/3644 F-ZTAT, H8/3643
F-ZTAT, H8/3642 AF-ZTAT), programs can be written and erased with a general-purpose PROM
programmer. In the on-chip flash memory versions, programs can be written and erased on-board.
6.1.1

Block Diagram

Figure 6.1 shows a block diagram of the on-chip ROM.
H'0000
H'0002
H'7FFE

Section 6 ROM

Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
H'0000
H'0002
On-chip ROM
H'7FFE
Even-numbered
address
Figure 6.1 ROM Block Diagram (H8/3644)
H'0001
H'0003
H'7FFF
Odd-numbered
address
Rev. 6.00 Sep 12, 2006 page 103 of 526
Section 6 ROM
REJ09B0326-0600