h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 629

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

20.3
20.3.1
When the RAME bit is set to 1, accesses to H8S/2138, H8S/2134, and H8S/2133 addresses
H'(FF)E080 to H'(FF)EFFF and H'(FF)FF00 to H'(FF)FF7F, and H8S/2137, H8S/2132, and
H8S/2130 addresses H'(FF)E880 to H'(FF)EFFF and H'(FF)FF00 to H'(FF)FF7F, are directed to
the on-chip RAM. When the RAME bit is cleared to 0, accesses to addresses H'(FF)E080 to
H'(FF)EFFF and H'(FF)FF00 to H'(FF)FF7F, are directed to the off-chip address space.
Since the on-chip RAM is connected to the bus master by a 16-bit data bus, it can be written to
and read in byte or word units. Each type of access is performed in one state.
Even addresses use the upper 8 bits, and odd addresses use the lower 8 bits. Word data must start
at an even address.
20.3.2
When the RAME bit is set to 1, accesses to H8S/2138, H8S/2134, and H8S/2133 addresses
H'(FF)E080 to H'(FF)EFFF and H'(FF)FF00 to H'(FF)FF7F, and H8S/2137, H8S/2132, and
H8S/2130 addresses H'(FF)E880 to H'(FF)EFFF and H'(FF)FF00 to H'(FF)FF7F, are directed to
the on-chip RAM. When the RAME bit is cleared to 0, the on-chip RAM is not accessed.
Undefined values are read from these bits, and writing is invalid.
Since the on-chip RAM is connected to the bus master by a 16-bit data bus, it can be written to
and read in byte or word units. Each type of access is performed in one state.
Even addresses use the upper 8 bits, and odd addresses use the lower 8 bits. Word data must start
at an even address.
Operation
Expanded Mode (Modes 1, 2, and 3 (EXPE = 1))
Single-Chip Mode (Modes 2 and 3 (EXPE = 0))
Rev. 4.00 Jun 06, 2006 page 575 of 1004
REJ09B0301-0400
Section 20 RAM