220
Chapter 8
Interrupt/Exception Processing Function
Preliminary User’s Manual U15839EE1V0UM00
8.3.6 In-service priority register (ISPR)
This register holds the priority level of the maskable interrupt currently acknowledged. When an inter-
rupt request is acknowledged, the bit of this register corresponding to the priority level of that interrupt
request is set to 1 and remains set while the interrupt is serviced.
When the RETI instruction is executed, the bit corresponding to the interrupt request having the highest
priority is automatically reset to 0 by hardware. However, it is not reset to 0 when execution is returned
from non-maskable interrupt servicing or exception processing.
This register is read-only in 8-bit or 1-bit units.
Figure 8-12:
In-Service Priority Register (ISPR)
Remark:
n = 0 to 7 (priority level)
8.3.7 Maskable interrupt status flag (ID)
The ID flag is bit 5 of the PSW and this controls the maskable interrupt’s operating state, and stores
control information regarding enabling or disabling of interrupt requests.
Figure 8-13:
Maskable Interrupt Status Flag (ID)
7
6
5
4
3
2
1
0
Address
Initial
value
ISPR
ISPR7
ISPR6
ISPR5
ISPR4
ISPR3
ISPR2
ISPR1
ISPR0
FFFFF19AH
00H
Bit Position
Bit Name
Function
7 to 0
ISPR7 to
ISPR0
Indicates priority of interrupt currently acknowledged
0: Interrupt request with priority n not acknowledged
1: Interrupt request with priority n acknowledged
31
8 7 6 5 4 3 2 1 0
Initial
value
PSW
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0 NP EP ID SAT CY OV S Z 00000020H
Bit Position
Bit Name
Function
5
ID
Indicates whether maskable interrupt processing is enabled or disabled.
0: Maskable interrupt request acknowledgement enabled
1: Maskable interrupt request acknowledgement disabled (pending)
This bit is set to 1 by the DI instruction and reset to 0 by the EI instruction. Its value is
also modified by the RETI instruction or LDSR instruction when referencing to PSW.
Non-maskable interrupt requests and exceptions are acknowledged regardless of this
flag. when a maskable interrupt is acknowledged, the ID flag is automatically set to 1
by hardware.
The interrupt request generated during the acknowledgement disabled period (ID = 1)
is acknowledged when the PIFn bit of PICn register is set to 1, and the ID flag is reset
to 0.
Содержание mPD703128
Страница 6: ...6 Preliminary User s Manual U15839EE1V0UM00 ...
Страница 20: ...20 Preliminary User s Manual U15839EE1V0UM00 ...
Страница 32: ...32 Preliminary User s Manual U15839EE1V0UM00 MEMO ...
Страница 154: ...154 Preliminary User s Manual U15839EE1V0UM00 MEMO ...
Страница 238: ...238 Preliminary User s Manual U15839EE1V0UM00 MEMO ...
Страница 356: ...356 Preliminary User s Manual U15839EE1V0UM00 MEMO ...
Страница 522: ...522 Preliminary User s Manual U15839EE1V0UM00 MEMO ...
Страница 600: ...600 Preliminary User s Manual U15839EE1V0UM00 MEMO ...
Страница 610: ...610 Preliminary User s Manual U15839EE1V0UM00 ...
Страница 612: ......