Altera RapidIO MegaCore Function - Manual (Page 111)

Chapter 4: Functional Description 4–65
Error Detection and Management
August 2014 Altera Corporation RapidIO MegaCore Function
User Guide
1 These errors do not cause any of the standard-defined errors to be declared and
recorded in the Error Management registers.
Port-Write Reception Module
The Port-Write reception module processes receive port-write request MAINTENANCE
packets. The following bits in the Maintenance Interrupt register (
Table 6–26 ) in the
implementation-defined space report any detected anomaly. The System Maintenance
Avalon-MM slave port interrupt signal sys_mnt_s_irq is asserted if the
corresponding bit in the Maintenance Interrupt Enable register (
Table 6–27 ) is set.
■ The PORT_WRITE_ERROR bit is set when the packet is either too small (no payload) or
too large (more than 64 bytes of payload), or if the actual size of the packet is larger
than indicated by the wrsize field. These errors do not cause any of the standard
defined errors to be declared and recorded in the error management registers.
■ The PACKET_DROPPED bit is set when a port-write request packet is received but
port-write reception is not enabled (by setting bit PORT_WRITE_ENA in the Rx Port
Write Control
register, described in Table 6–36 on page 6–19 ) or if a previously
received port-write has not been read out from the Rx Port Write Buffer register
(
Table 6–38 on page 6–20 ).
Port-Write Transmission Module
Port-write requests do not cause response packets to be generated. Therefore, the
port-write transmission module does not detect or report any errors.
Input/Output Avalon-MM Slave
The I/O Avalon-MM slave module creates request packets for the Avalon-MM
transaction on its read and write slave interfaces and processes the response packets
that it receives. Anomalies are reported through one or more of the following three
channels:
■ Standard error management registers
■ Registers in the implementation defined space
■ The Avalon-MM slave interface's error indication signal
Standard Error Management Registers
The following standard defined error types can be declared by the I/O Avalon-MM
slave module. The corresponding error bits are then set and the required packet
information is captured in the appropriate error management registers.
■ IO Error Response is declared when a response with ERROR status is received for a
pending NREAD or NWRITE_R request.
■ Unsolicited Response is declared when a response is received that does not
correspond to any pending NREAD or NWRITE_R request.
■ Packet Response Time-Out is declared when a response is not received within the
time specified by the Port Response Time-Out Response CSR ( Table 6–7 on
page 6–6 ) for an NREAD or NWRITE_R request.