Interrupt Priority Register; Irq Highest-Priority Register - Intel IXP45X Developer's Manual

Interrupt Controller—Intel
17.6.6

Interrupt Priority Register

Register Name:
0xC800 3014
Physical Address:
The highest eight priority interrupts can be programmed via this register, each of the 3-bit
Register
sets can be programmed to any priority from 0(000) through 7(111). This register applies
Description:
to both IRQ and FIQ interrupts.
Access: Read/Write.
31
Reserved
Register
Bits Name
31:24 Reserved
23:21 Prior_Intbus7 [2:0]
20:18 Prior_Intbus6 [2:0]
17:15 Prior_Intbus5 [2:0]
14:12 Prior_Intbus4 [2:0]
11:9 Prior_Intbus3 [2:0]
8:6 Prior_Intbus2 [2:0]
5:3 Prior_Intbus1 [2:0]
2:0 Prior_Intbus0 [2:0]
17.6.7

IRQ Highest-Priority Register

Register Name:
0xC800 3018
Physical Address:
This register returns the "incremented number" of the highest-priority interrupt that is
pending for the IRQ. For example, if interrupt 0 is the highest IRQ pending, the register
returns 1. If the register returns 0, it means that there is no interrupt pending or a spurious
Register
interrupt.
Description:
Note that the encoded number is shifted left by two bits, a software requirement for the
value to be multiplied by 4 before being read. This allows the register's contents to be
directly used as an offset into a jump table for interrupt vectoring.
Access: Read.
31
Register
Bits Name
31:9 Reserved
8:2 IRQ_ENC_ST
1:0 Reserved
August 2006
Reference Number: 306262-004US
® ®
IXP45X and Intel IXP46X Product Line of Network Processors
24 23
Reserved, Read as undefined, write as 0
Set the priority of the Intr_bus [7]; default is 7
Set the priority of the Intr_bus [6]; default is 6
Set the priority of the Intr_bus [5]; default is 5
Set the priority of the Intr_bus [4]; default is 4
Set the priority of the Intr_bus [3]; default is 3
Set the priority of the Intr_bus [2]; default is 2
Set the priority of the Intr_bus [1]; default is 1
Set the priority of the Intr_bus [0]; default is 0
Reserved
Description
Reserved, Read as undefined, write as 0
Indicates the highest priority pending interrupt (the interrupt
"number" incremented by 1)
Reserved, Read as undefined, write as 0
INTR_PRTY
0x00FAC688
Reset Hex Value:
Interrupt Priority selects
INTR_PRTY
Description
INTR_IRQ_ENC_ST
0x00000000
Reset Hex Value:
INTR_IRQ_ENC_ST
® ®
Intel IXP45X and Intel IXP46X Product Line of Network Processors
Reset Value Access
0x00 RW
111 RW
110 RW
101 RW
100 RW
011 RW
010 RW
001 RW
000 RW
8 2 1
IRQ_ENC_ST
Reset Value Access
0x000000 RO
0x00 RO
0x0 RO
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