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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Interrupt Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
816
Reference Number: 306262-004US
17.6.8
FIQ Highest-Priority Register
The additional bit defined (i.e. bit 8) of the highest priority register is in the same bit
position as the extended register address. The higher bit of the status can be used as
part of the address calculation to determine which group of registers to access.
17.6.9
Error High Priority Enable Register
§ §
Register Name:
INTR_FIQ_ENC_ST
Physical Address:
0xC800 301C
Reset Hex Value:
0x00000000
Register
Description:
This register returns the “incremented number” of the highest-priority interrupt that is
pending for the FIQ. For example, if interrupt ‘0’ is the highest FIQ pending, the register
returns 1.
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
8
2
1
0
Reserved
FRQ_ENC_ST
Rsvd
Register
INTR_FIQ_ENC_ST
Bits
Name
Description
Reset Value
Access
31:9
Reserved
Reserved, Read as undefined, write as 0
0x000000
RO
8:2
FIQ_ENC_ST
Indicates the highest-priority, pending fast interrupt (the interrupt
“number” incremented by 1)
0x00
RO
1:0
Reserved
Reserved, Read as undefined, write as 0
0x0
RO
Register Name:
ERROR_EN2
Physical Address:
0xC800 3034
Reset Hex Value:
0x00000000
Register
Description:
This register decides if an interrupt is to be presented to the Intel XScale
®
Processor above all other
priorities. This affects the priority only, not the number reported in the *_ENC_ST registers. Bit 0 of this
register corresponds to interrupt 32 and bit 31 corresponds to interrupt 63.
Access: Read/Write.
31
0
Error High Priority Enable[63:32]