HD64F2638F20J Datasheet, PDF (787/1512 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 20 RAM
Section 20 RAM
Note: The H8S/2635 Group is not equipped with a DTC.
20.1 Overview
The H8S/2636 has 4 kbytes, and H8S/2638, H8S/2639, and H8S/2630 have 16 kbytes of on-chip
high-speed static RAM. The H8S/2635 has 6 kbytes of on-chip RAM. The RAM is connected to
the CPU by a 16-bit data bus, enabling one-state access by the CPU to both byte data and word
data. This makes it possible to perform fast word data transfer.
The on-chip RAM can be enabled or disabled by means of the RAM enable bit (RAME) in the
system control register (SYSCR).
20.1.1 Block Diagram
Figure 20-1 shows a block diagram of the on-chip RAM.
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
H'FFE000
H'FFE002
H'FFE004
H'FFE001
H'FFE003
H'FFE005
H'FFEFBE
H'FFFFC0
H'FFEFBF
H'FFFFC1
H'FFFFFE
H'FFFFFF
Figure 20-1 (a) Block Diagram of RAM (H8S/2636)
REJ09B0103-0800 Rev. 8.00
May 28, 2010
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