S1C88348/317/316/308 TECHNICAL HARDWARE
EPSON
I-19
3 CPU AND BUS CONFIGURATION
s Expanded 512K minimum mode
The expanded 512K minimum mode setting
applies when the S1C883xx is used with over
64K bytes and less than 512K bytes
× 4 of
external expanded memory. This mode is
usable regardless of the MCU/MPU mode
setting.
Because internal ROM is being used in the MCU
mode, external memory can be assigned to the
area from 080000H to 27FFFFH.
Since the internal ROM area is released in the
MPU mode, external memory can be assigned
to the area from 000000H to 1FFFFFH. How-
ever, the area from 00F000H to 00FFFFH is
assigned to internal memory and cannot be
used to access an external device.
CPU operation in this mode is equivalent to the
S1C88 core CPU Model3 minimum mode. The
area within physical space 000000H to 1FFFFFH
in the MPU mode or physical space 080000H to
27FFFFH + internal memory in the MCU mode
is effective as a target for accessing.
Furthermore, since program memory expansion
is limited to less than 64K bytes configured with
the common area (000000H to 007FFFH) and
one optional bank area (internal ROM + 32K in
the MCU mode), this mode is suitable for small-
to mid-scale program memory and large-scale
data memory systems.
The address range of chip enable (CE) signals in
this mode is fixed at 512K bytes.
Fig. 3.5.2.3 Memory map for the expanded 512K minimum mode
S1C88308
- MCU mode -
27FFFFH
:
080000H
07FFFFH
010000H
00FFFFH
00F000H
00EFFFH
:
00C000H
00BFFFH
004000H
003FFFH
002000H
001FFFH
000000H
- MPU mode -
External
memory area
Internal memory
External
memory area
External
memory area
Internal memory
Unused area
Internal memory
1FFFFFH
S1C88317/316
- MCU mode -
External
memory area
Internal memory
Unused area
Internal memory
Unused area
S1C88348
- MCU mode -
External
memory area
Internal memory
Unused area
Internal memory
Unused area
See Figure 3.2.1 for the internal memory