3069RF-ZTAT Datasheet, PDF (593/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER

Section 17 RAM
17.1 Overview
The H8/3069R 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 H8/3069R 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. 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. 5.0, 09/04, page 571 of 978