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8 EPSON S1C88650 TECHNICAL MANUAL
3 CPU AND BUS CONFIGURATION
3 CPU AND BUS CONFIGURATION
In this section, we will explain the CPU, operating mode and bus configuration.
3.1 CPU
The S1C88650 utilize the S1C88 8-bit core CPU
whose resistor configuration, command set, etc. are
virtually identical to other units in the family of
processors incorporating the S1C88.
See the "S1C88 Core CPU Manual" for the S1C88.
Specifically, the S1C88650 employ the Model 3
S1C88 CPU which has a maximum address space of
1M bytes × 3.
3.2 Internal Memory
The S1C88650 is equipped with internal ROM and
RAM as shown in Figure 3.2.1. Small scale applica-
tions can be handled by one chip. It is also possible
to utilize internal memory in combination with
external memory.
Furthermore, internal ROM can be disconnected
from the bus and the resulting space released for
external applications.
0EFFFFH
010000H
00FFFFH
00FF00H
00FD7FH
00F800H
00F7FFH
00D800H
00D7FFH
:
00C000H
00BFFFH
000000H
Kanji font ROM
(896K bytes)
I/O memory
Display memory
RAM (8K bytes)
Unused
area
ROM
(48K bytes)
Fig. 3.2.1 Internal memory map
3.2.1 Program ROM
The S1C88650 has a built-in 48K-byte program
ROM. The ROM is allocated to 000000H–00BFFFH.
This ROM areas shown above can be released to
external memory depending on the setting of the
_______
MCU/MPU terminal. (See "3.5 Chip Mode".)
3.2.2 RAM
The internal RAM capacity is 8K bytes and is
allocated to 00D800H–00F7FFH.
Even when external memory which overlaps the
internal RAM area is expanded, the RAM area is
not released to external memory. Access to this area
is via internal RAM.
3.2.3 I/O memory
A memory mapped I/O method is employed in the
S1C88650 for interfacing with internal peripheral
circuit. Peripheral circuit control bits and data
register are arranged in data memory space.
Control and data exchange are conducted via
normal memory access. I/O memory is arranged in
page 0: 00FF00H–00FFFFH area.
See Section 5.1, "I/O Memory Map", for details of
the I/O memory.
Even when external memory which overlaps the I/
O memory area is expanded, the I/O memory area
is not released to external memory. Access to this
area is via I/O memory.
3.2.4 Display memory
The S1C88650 is equipped with an internal display
memory which stores a display data for LCD
driver.
Display memory is arranged in page 0: 00Fx00H–
00Fx7FH (x = 8–DH) in the data memory area. See
Section 5.11, "LCD Driver", for details of the display
memory. Like the I/O memory, display memory
cannot be released to external memory.
3.2.5 Kanji font ROM
The S1C88650 has a built-in kanji font ROM that
can be used to store JIS level-1 and level-2 kanji
sets, alphanumeric characters and music shift-JIS
characters.
The kanji font ROM capacity is 896K bytes and is
allocated to 010000H–0EFFFFH.
When the kanji font is not used the remaining area
or the entire area can be used for a program and
data storage area (see the "S5U1C88xxxRx Manual"
for use of font data).
This ROM areas shown above can be released to
external memory depending on the setting of the
_______
MCU/MPU terminal. (See "3.5 Chip Mode".)