AXI Bridge for PCI Express v2.4
29
PG055 June 4, 2014
Chapter 2:
Product Specification
Bridge Status and Control Register (Offset 0x134)
The Bridge Status and Control register (described in
) provides information about
the current state of the AXI4-Stream Bridge. It also provides control over how reads and
writes to the Core Configuration Access aperture are handled.
Interrupt Decode Register (Offset 0x138)
The Interrupt Decode register (described in
) provides a single location where the
host processor interrupt service routine can determine what is causing the interrupt to be
asserted and how to clear the interrupt. Writing a
1'b1
to any bit of the Interrupt Decode
register clears that bit except for the Correctable, Non-Fatal, and Fatal bits.
Follow this sequence to clear the Correctable, Non-Fatal, and Fatal bits:
1. Clear the Root Port Error FIFO (0x154) by performing first a read, followed by write-back
of the same register.
2. Write to the Interrupt Decode Register (0x138) with ‘1’ to the appropriate error bit to
clear it.
IMPORTANT:
An asserted bit in the Interrupt Decode register does not cause the interrupt line to assert
unless the corresponding bit in the Interrupt Mask register is also set.
Table 2-11:
Bridge Status and Control Register
Bits
Name
Core
Access
Reset
Value
Description
0
ECAM Busy
RO
0
Indicates an ECAM access is in progress (waiting for
completion).
7:1
Reserved
RO
0
Reserved
8
Global
Disable
RW
0
When set, disables interrupt line from being asserted. Does not
prevent bits in Interrupt Decode register from being set.
15:9
Reserved
RO
0
Reserved
16
RW1C as RW
RW
0
When set, allows writing to core registers which are normally
RW1C.
17
RO as RW
RW
0
When set, allows writing to certain registers which are normally
RO.
(Only supported for Kintex-7 FPGA cores.)
31:18 Reserved
RO
0
Reserved