HD6475348R Datasheet, PDF (313/487 Pages) Hitachi Semiconductor – Single-Chip Microcomputer

Section 16 RAM
16.1 Overview
The H8/534 and H8/536 include 2 kbytes of on-chip static RAM, connected to the CPU by a
16-bit data bus. Both byte and word access to the on-chip RAM are performed in two states,
enabling rapid data transfer and instruction execution.
The on-chip RAM is assigned to addresses H'F680 to H'FE7F in the chip’s address space. A
RAM control register (RAMCR) can enable or disable the on-chip RAM, permitting these
addresses to be allocated to external memory instead, if so desired.
16.1.1 Block Diagram
Figure 16-1 shows the block diagram of the on-chip RAM.
Internal data bus (upper 8 bits)
Internal data bus (lower 8 bits)
Address
H'F680
H'F682
RAMCR
H'FE7E
On-chip RAM
Even addresses
Odd addresses
RAMCR: RAM Control Register
Figure 16-1 Block Diagram of On-Chip RAM
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