User’s Manual
C166S V1 SubSystem
Central Processing Unit
User’s Manual
3-21
V 1.6, 2001-08
PSW. The CPU denies all requests in case of a cleared IEN flag. If the requester has a
lower or equal priority level than current CPU task, the request stays pending.
Note: Priority level 0000
B
is the default level of the CPU. Therefore, a request on ILVL
0000
B
will be arbitrated, but the CPU will never accept an action request on this
level. However, every enabled interrupt request (including all denied interrupt
requests - also priority level 0000
B
requests) triggers a CPU wake-up from idle
state independent of the setting of the global interrupt enable bit PSW.IEN.
Note: The first 16 trap numbers are reserved for the CPU traps. The first usable interrupt
trap number starts with 10
H
. Therefore, the number of interrupt nodes is limited to
112.
All interrupt control registers are organized identically. The lower 8 bits of an interrupt
control register contain the complete interrupt control and status information of the
associated source, which is required during one round of prioritization (arbitration cycle).
The upper 8 bits of the respective register are reserved. All interrupt control registers are
bit-addressable, and all bits can be read or written via software. Therefore, each interrupt
source can be programmed or modified with just one instruction. When reading the
interrupt control registers with instructions that operate with word data types, the upper
8 bits (15...8) will return zeros. Zeros should always be written to these bit positions. The
layout of the interrupt control registers shown below is applicable to all xxIC registers.
xxIC
Interrupt Control Register
bSFR(xxxx
H
,xx
H
)
Reset value: 0000
H
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
xxGP xxIR
xxIE
ILVL
GLVL
r
r
r
r
r
r
r
rw
rwh
rw
rw
rw
Field
Bits
Type Description
xxGP
[8]
rw
Group Priority Extension
Defines the value of high-order group level bit
xxIR
1)
[7]
rwh
Interrupt Request Flag
0
No request pending
1
This source has raised an interrupt request
xxIE
[6]
rw
Interrupt Enable Control Bit
(individually enables/disables a specific source)
0
Interrupt request is disabled
1
Interrupt request is enabled
Содержание C166S V1 SubSystem
Страница 10: ...User s Manual C166S V1 SubSystem User s Manual I 6 V 1 6 2001 08...
Страница 16: ...User s Manual C166S V1 SubSystem Introduction User s Manual 1 6 V 1 6 2001 08...
Страница 126: ...User s Manual C166S V1 SubSystem Central Processing Unit User s Manual 3 96 V 1 6 2001 08...
Страница 178: ...User s Manual C166S V1 SubSystem Memory Organization User s Manual 4 52 V 1 6 2001 08...
Страница 206: ...User s Manual C166S V1 SubSystem Instruction Set User s Manual 5 28 V 1 6 2001 08...
Страница 306: ...User s Manual C166S V1 SubSystem Detailed Instruction Set User s Manual 6 100 V 1 6 2001 08...
Страница 362: ...User s Manual C166S V1 SubSystem The External Bus Interface User s Manual 8 40 V 1 6 2001 08...
Страница 452: ...User s Manual C166S V1 SubSystem General Purpose Timer Unit User s Manual 12 44 V 1 6 2001 08...
Страница 454: ...User s Manual C166S V1 SubSystem Instruction Index User s Manual 13 2 V 1 6 2001 08...
Страница 459: ......