HD64F2638F20J Datasheet, PDF (899/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
Section 21C ROM
(H8S/2635 Group)
Section 21C ROM
(H8S/2635 Group)
21C.1 Overview
The H8S/2635 Group has 192 kbytes of on-chip flash memory, or 192 kbytes or 128 kbytes of on-
chip 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 to MD0).
The flash memory version can be erased and programmed on-board, as well as with a special-
purpose PROM programmer.
21C.1.1 Block Diagram
Figure 21C-1 shows a block diagram of 192-kbyte and 128-kbyte ROM.
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
H'000000
H'000002
H'000001
H'000003
H'02FFFE
(H'01FFFE)*
H'02FFFF
(H'01FFFF)*
Note: * ROM addresses for the H8S/2635 extend from H'000000 to H'02FFFF (192 kbytes),
and for the H8S/2634 from H'000000 to H'01FFFF (128 kbytes).
Figure 21C-1 Block Diagram of ROM 192 kbytes (128 kbytes)^*
REJ09B0103-0800 Rev. 8.00
May 28, 2010
Page 849 of 1458