S1C88650 TECHNICAL MANUAL EPSON 9
3 CPU AND BUS CONFIGURATION
When multiple exception processing factors are
generated at the same time, execution starts with
the highest priority item.
The priority sequence shown in Table 3.3.1 assumes
that the interrupt priority levels are all the same.
The interrupt priority levels can be set by software
in each system. (See Section 5.14, "Interrupt and
Standby Status".)
Note: For exception processing other than reset,
SC (system condition flag) and PC (program
counter) are evacuated to the stack and
branches to the exception processing
routines. Consequently, when returning to
the main routine from exception processing
routines, please use the RETE instruction.
See the "S1C88 Core CPU Manual" for information
on CPU operations when an exception processing
factor is generated.
3.4 CC (Customized Condition Flag)
The S1C88650 does not use the customized condi-
tion flag (CC) in the core CPU. Accordingly, it
cannot be used as a branching condition for the
conditional branching instruction (JRS, CARS).
3.5 Chip Mode
3.5.1 MCU mode and MPU mode
The chip operating mode can be set to one of two
_______
settings using the MCU/MPU terminal.
■_______
MCU mode...Set the MCU/MPU terminal to HIGH
Switch to this setting when using internal ROM.
With respect to areas other than internal
memory, external memory can even be
expanded. See Section 3.5.2, "Bus mode", for the
memory map.
In the MCU mode, during initial reset, only
systems in internal memory are activated.
Internal program ROM is normally fixed as the
top portion of the program memory from the
common area (logical space 0000H–7FFFH).
Exception processing vectors are assigned in
internal program ROM. Furthermore, the
application initialization routines that start with
reset exception processing must likewise be
written to internal program ROM. Since bus and
other settings which correlate with external
expanded memory can be executed in software,
this processing is executed in the initialization
routine written to internal program ROM. Once
these bus mode settings are made, external
memory can be accessed.
3.3 Exception Processing Vectors
000000H–00004BH in the program area of the
S1C88650 is assigned as exception processing
vectors. Furthermore, from 00004EH to 0000FFH,
software interrupt vectors are assignable to any two
bytes which begin with an even address.
Table 3.3.1 lists the vector addresses and the
exception processing factors to which they corre-
spond.
Table 3.3.1 Exception processing vector table
Vector
address
000000H
000002H
000004H
000006H
000008H
00000AH
00000CH
00000EH
000010H
000012H
000014H
000016H
000018H
00001AH
00001CH
00001EH
000020H
000022H
000024H
000026H
000028H
00002AH
00002CH
00002EH
000030H
000032H
000034H
000036H
000038H
00003AH
00003CH
00003EH
000040H
000042H
000044H
000046H
000048H
00004AH
00004CH
00004EH
:
0000FEH
Priority
High
↑
↓
Low
No
priority
rating
Exception processing factor
Reset
Zero division
Watchdog timer (NMI)
K07 input interrupt
K06 input interrupt
K05 input interrupt
K04 input interrupt
K03 input interrupt
K02 input interrupt
K01 input interrupt
K00 input interrupt
PTM 0 underflow interrupt
PTM 0 compare match interrupt
PTM 1 underflow interrupt
PTM 1 compare match interrupt
PTM 2 underflow interrupt
PTM 2 compare match interrupt
PTM 3 underflow interrupt
PTM 3 compare match interrupt
System reserved (cannot be used)
Serial I/F error interrupt
Serial I/F receiving complete interrupt
Serial I/F transmitting complete interrupt
System reserved (cannot be used)
System reserved (cannot be used)
System reserved (cannot be used)
Clock timer 32 Hz interrupt
Clock timer 8 Hz interrupt
Clock timer 2 Hz interrupt
Clock timer 1 Hz interrupt
PTM 4 underflow interrupt
PTM 4 compare match interrupt
PTM 5 underflow interrupt
PTM 5 compare match interrupt
PTM 6 underflow interrupt
PTM 6 compare match interrupt
PTM 7 underflow interrupt
PTM 7 compare match interrupt
System reserved (cannot be used)
Software interrupt
For each vector address and the address after it, the
start address of the exception processing routine is
written into the subordinate and super ordinate
sequence. When an exception processing factor is
generated, the exception processing routine is
executed starting from the recorded address.