IDT sRIO Ports
Revision 1.5
Integrated Device Technology, Inc.
CPS-16/12/8 User Manual
2 - 7
July 10, 2012
2.2.7 Errored Packets
The device does not trace packets with physical errors such as packet with CRC errors and packets that
are longer than 276 bytes. The device traces packets with logical errors (ex. invalid type) as long as they
match the trace criteria.
2.2.8 Trace Configuration
The Trace Function is enabled globally for the device with a write to the CPS_CONTROL register. When
global trace is enabled the Trace Output Port defined in the CPS_CONTROL register will be enabled. The
CPS_CONTROL register is used to control the mode of the Trace Output Port (Default or Trace only).
Each port supports an enable of each of its four trace criteria values in its respective PORT_n_OPS
register. This will be independent such that a match on any given value does not depend on a match of any
other value. The PORT_n_OPS register will also control whether or not a packet that matches a given port’s
trace criteria will cause the device to generate a Port Write packet.
2.2.9 Cut Through with Trace
The device supports Cut Through when Trace is enabled
(see
section 2.1.4.2).
2.3 PACKET FILTERING
Along with the ability to trace packets via comparisons against up to four comparison values, the CPS
device supports the ability to filter packet based on comparisons against these same values. If this packet
filtering is enabled, a successful comparison of the first 160 bits in a received packet to a port’s pre-
programmed values will result in the packet being dropped or “filtered” by the device. Note that a successful
comparison will also prevent a maintenance packet from being “accepted/processed” by the CPS device (in
the event that a maintenance packet that met the filter criteria had a hop count of 0).
The device supports the ability for the packet filtering to be enabled/disable at each port individually for
each unique comparison value at that port.
The device provides the ability to enable/disable packet trace and packet filtering simultaneously for each
port individually for each unique comparison value at that port. If both packet filtering and packet trace are
enabled and a match occurs between a received packet and a comparison value, then the packet will be
dropped but will also be traced to the specified trace output port. If packet filtering is enabled but trace is
not, then the packet will be filtered and not traced to the specified output trace port.
The device provides a counter at each port for each comparison value. The counter provides a continuous
count of the number of packets that have been filtered at each port as a result of a successful match against
each comparison value.
2.4 SOFTWARE ASSISTED ERROR RECOVERY
Each port supports the software assisted error recovery registers defined in the rev 1.3 revision of the SRIO
specification. Specifically these registers include the Port n Link Maintenance CSRs, the Port n Link Mainte-
nance Response CSRs, and the Port n Local ACKID CSRs. A set of each of these three registers are
provided per port.
2.4.1 Usage Definition for Port n Link Maintenance CSRs
A write to these registers will force CPS to transmit a Link Request Symbol on the associated link. The
command field in the transmitted symbol will be the contents of the command field written into this register.
A read of this register will return the value of the command field in the register.
Support is provided for two command field values: 1) Reset (0b011), and 2) Input Status (0b100)
In the case where packet does not match the filter and TRACE_OUTPUT_PORT_MODE is set
to a 1, the packet will not be routed to the destined port. IDT recommends to set the
TRACE_OUTPUT_PORT_MODE to 0 when only packet filtering is enabled.
