Chapter 10: Optional Features
10–3
ECRC
November 2012
Altera Corporation
Arria V GZ Hard IP for PCI Express
ECRC on the RX Path
When the
ECRC generation
option is turned on, errors are detected when receiving
TLPs with a bad ECRC. If the
ECRC generation
option is turned off, no error
detection occurs. If the
ECRC forwarding
option is turned on, the ECRC value is
forwarded to the Application Layer with the TLP. If the
ECRC forwarding
option is
turned off, the ECRC value is not forwarded.
summarizes the RX ECRC functionality for all possible conditions.
ECRC on the TX Path
When the
ECRC generation
option is on, the TX path generates ECRC. If you turn on
ECRC forwarding
, the ECRC value is forwarded with the TLP.
summarizes the TX ECRC generation and forwarding. In this table, if
TD
is 1, the TLP
includes an ECRC.
TD
is the TL digest bit of the TL packet described in
Transaction Layer Packet (TLP) Header Formats
.
Table 10–2. ECRC Operation on RX Path
ECRC
Forwarding
ECRC
Check
Enable
ECRC
Status
Error
TLP Forward to Application Layer
No
No
none
No
Forwarded
good
No
Forwarded without its ECRC
bad
No
Forwarded without its ECRC
Yes
none
No
Forwarded
good
No
Forwarded without its ECRC
bad
Yes
Not forwarded
Yes
No
none
No
Forwarded
good
No
Forwarded with its ECRC
bad
No
Forwarded with its ECRC
Yes
none
No
Forwarded
good
No
Forwarded with its ECRC
bad
Yes
Not forwarded
:
(1) The
ECRC Check Enable
field is in the
Configuration Space Advanced Error Capabilities and
Control Register
.
Table 10–3. ECRC Generation and Forwarding on TX Path
ECRC
Forwarding
ECRC
Generation
Enable
TLP on Application
TLP on Link
Comments
No
No
TD
=0, without ECRC
TD
=0, without ECRC
TD
=1, without ECRC
TD
=0, without ECRC
Yes
TD
=0, without ECRC
TD
=1, with ECRC
ECRC is generated
TD
=1, without ECRC
TD
=1, with ECRC