Chapter 6: IP Core Interfaces
6–35
Transaction Layer Configuration Space Signals
November 2012
Altera Corporation
Arria V GZ Hard IP for PCI Express
Transaction Layer Configuration Space Signals
Table 6–13
describes the Transaction Layer Configuration Space signals.
cpl_err[6:0]
(continued)
■
cpl_err[4]
: Unsupported Request (UR) error for posted TLP. The
Application Layer asserts this signal to treat a posted request as an
Unsupported Request. The Hard IP automatically sets the error status bits in
the Configuration Space register and sends error messages in accordance
with the
PCI Express Base Specification
. Many cases of Unsupported
Requests are detected and reported internally by the Transaction Layer. For a
list of these cases, refer to
“Transaction Layer Errors” on page 13–3
I
■
cpl_err[5]
: Unsupported Request error for non-posted TLP. The Application
Layer asserts this signal to respond to a non-posted request with an
Unsupported Request (UR) completion. In this case, the Application Layer
sends a completion packet with the Unsupported Request status back to the
requestor, and asserts this error signal. The Hard IP automatically sets the
error status bits in the Configuration Space Register and sends error
messages in accordance with the
PCI Express Base Specification
. Many
cases of Unsupported Requests are detected and reported internally by the
Transaction Layer. For a list of these cases, refer to
.
■
cpl_err[6]
: Log header. If header logging is required, this bit must be set in
the every cycle in which any of
cpl_err[2]
,
cpl_err[3]
,
cpl_err[4]
, or
cpl_err[5]
is set. The Application Layer presents the header to the Hard IP
by writing the following values to the following 4 registers using LMI before
asserting
cpl_err[6]
:
■
lmi_addr: 12'h81C,
lmi_din
:
err_desc_func0[127:96]
■
lmi_addr: 12'h820,
lmi_din
:
err_desc_func0[95:64]
■
lmi_addr: 12'h824,
lmi_din
:
err_desc_func0[63:32]
■
lmi_addr: 12'h828,
lmi_din
:
err_desc_func0[31:0]
Refer to the
for more information about LMI
signalling.
cpl_pending
I
Completion pending. The Application Layer must assert this signal when a
master block is waiting for completion, for example, when a transaction is
pending.
Table 6–12. Completion Signals for the Avalon-ST Interface (Part 2 of 2)
Signal
I/O
Description
Table 6–13. Configuration Space Signals (Hard IP Implementation) (Part 1 of 2)
Signal
Dir
Description
tl_cfg_add[3:0]
0
Address of the register that has been updated. This signal is an index indicating which
Configuration Space register information is being driven onto
tl_cfg_ctl.
The indexing is
defined in
. The index increments on every
pld_clk
.
tl_cfg_ctl[31:0]
0
The
tl_cfg_ctl
signal is multiplexed and contains the contents of the Configuration Space
registers. The information presented on this bus depends on the
tl_cfg_add
index
according to
tl_cfg_sts[52:0]
0
Configuration status bits. This information updates every
pld_clk
cycle. Refer to
Table 6–14
for a detailed description of the status bits.