HD6432633 Datasheet, PDF (949/1453 Pages) Renesas Technology Corp – Series of Microcomputers (MCUs: microcomputer units)

Section 22 ROM
22.1 Overview
The H8/2633 Series has 256 kbytes of on-chip flash memory, or 256, 192, or 128 kbytes of on-
chip mask ROM, the H8S/2633 and H8S/2633R have 256 kbytes of flash memory, and the
H8S/2695 has 192 kbytes of mask ROM. The ROM is connected to the bus master via a 16-bit
data bus, enabling both byte and word data to be accessed in one state. Instruction fetching is thus
speeded up, and processing speed increased.
The on-chip ROM is enabled and disabled by setting the mode pins (MD2, MD1, and MD0).
The flash memory version can be erased and programmed on-board, as well as with a special-
purpose PROM programmer.
22.1.1 Block Diagram
Figure 22-1 shows a block diagram of 256-kbyte ROM.
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
H'000000
H'000002
H'000001
H'000003
H'03FFFE
H'03FFFF
Figure 22-1 Block Diagram of ROM (256 kbytes)
22.1.2 Register Configuration
The H8/2633 Series operating mode is controlled by the mode pins and the MDCR register. The
register configuration is shown in table 22-1.
895