HD64F3028F25 Datasheet, PDF (601/925 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

Section 17 RAM
17.1 Overview
The H8/3028 Group has 16 kbytes RAM. The RAM is connected to the CPU by a 16-bit data bus.
The CPU accesses both byte data and word data in two states, making the RAM useful for rapid
data transfer.
The on-chip RAM of the H8/3028 Group is assigned to addresses H'FBF20 to H'FFF1F in modes
1, 2, and 7, and to addresses H'FFBF20 to H'FFFF1F in modes 3, 4, and 5,and to addresses H'E720
to H'FF1F in mode 6. The RAM enable bit (RAME) in the system control register (SYSCR) can
enable or disable the on-chip RAM.
17.1.1 Block Diagram
Figure 17.1 shows a block diagram of the on-chip RAM.
On-chip data bus (upper 8 bits)
On-chip data bus (lower 8 bits)
Bus interface
SYSCR
H'FBF20*
H'FBF22*
H'FBF21*
H'FBF23*
On-chip RAM
H'FFF1E*
Even addresses
H'FFF1F*
Odd addresses
Legend
SYSCR: System control register
Note: * Lower 20 bits of the address in mode 7.
Figure 17.1 RAM Block Diagram
Rev. 2.00, 09/03, page 569 of 890