CHAPTER 7 INTERRUPT/EXCEPTION PROCESSING FUNCTION
User’s Manual U12688EJ4V0UM00
218
7.3.5 In-service priority register (ISPR)
This register holds the priority level of the maskable interrupt currently acknowledged. When an interrupt request
is acknowledged, the bit of this register corresponding to the priority level of that interrupt request is set (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 cleared (0) by hardware. However, it is not cleared (0) when execution is returned from non-maskable
interrupt servicing or exception processing.
This register is read-only in 8- or 1-bit units.
Address
FFFFF166H
7
ISPR7
ISPR
6
ISPR6
5
ISPR5
4
ISPR4
3
ISPR3
2
ISPR2
1
ISPR1
0
ISPR0
After reset
00H
Bit Position
Bit Name
Function
7 to 0
ISPR7 to ISPR0
In-Service Priority Flag
Indicates priority of interrupt currently acknowledged.
0: Interrupt request with priority n not acknowledged
1: Interrupt request with priority n acknowledged
Remark
n = 0 to 7 (priority level)
7.3.6 Maskable interrupt status flag (ID)
The ID flag is bit 5 of the PSW.
This controls the maskable interrupt’s operating state, and stores control information on enabling/disabling
acknowledgement of interrupt requests.
31
0
PSW
After reset
00000020H
7
NP
6
EP
5
ID
4
SAT
3
CY
2
OV
1
S Z
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit Position
Bit Name
Function
5
ID
Interrupt Disable
Indicates whether maskable interrupt processing is enabled or disabled.
0: Maskable interrupt acknowledgement enabled
1: Maskable interrupt acknowledgement disabled (pending)
It 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 the
PSW.
Non-maskable interrupts 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 xxIFn bit of xxICn is set to 1, and the ID flag
is cleared to 0.
Содержание V850E/MS1 UPD703100
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