Section 11. Rom; Overview - Hitachi H8/329 Series Hardware Manual

11.1 Overview

The H8/329 includes 32k bytes of high-speed, on-chip ROM. The H8/328 has 24k bytes. The
H8/327 has 16k bytes. The H8/326 has 8k bytes. The on-chip ROM is connected to the CPU via a
16-bit data bus. Both byte data and word data are accessed in two states, enabling rapid data
transfer and instruction fetching.
The H8/329 and H8/327 are available with electrically programmable ROM (PROM). The PROM
version has a PROM mode in which the chip can be programmed with a standard PROM writer.
The on-chip ROM is enabled or disabled depending on the MCU operating mode, which is
determined by the inputs at the mode pins (MD
Table 11-1. On-Chip ROM Usage in Each MCU Mode
Mode
Mode 1 (expanded mode)
Mode 2 (expanded mode)
Mode 3 (single-chip mode)

Section 11. ROM

and MD
1
Mode pins
MD MD On-Chip ROM
1 0
0 1 Disabled (external addresses)
1 0 Enabled
1 1 Enabled
227
). See table 11-1.
0