User`s guide

DWMBB Adapter
3.12.6 XMI Errors
Table 3–16 lists the error bits and their descriptions for XMI-detected
errors that the DWMBB sets when the error occurs.
Table 3–16 XMI Error Bits
Bit Location Description
Transaction Timeout (TTO) XBER<13> Sets when a DWMBB-initiated DMA transaction times out
waiting for a response from a responder node, waiting to get an
XMI grant, or until the retry limit is reached. Once TTO sets, the
DMA transaction aborts and XMI error bits latch.
Command NO ACK (CNAK) XBER<15> Sets if the DMA transaction times out during an attempted
XMI C/A cycle. Examples of cases that cause CNAK to set
include the DWMBB trying to access nonexistent memory or the
responder node finding a parity error in the C/A cycle.
Read Error Response (RER) XBER<16> Sets if the DWMBB receives an RER from the responding XMI
memory node.
Read Sequence Error (RSE) XBER<17> Sets when the read data received by the DWMBB has data
cycles missing, if the data cycles are not in the proper sequence,
or if the DWMBB detects a parity error in a read data cycle.
Write Data NO ACK
(WDNAK)
XBER<19> Sets if the write data is NO ACKed by the XMI memory node,
which could be caused by a parity error on the XMI. The
DWMBB continues to retry the DMA write until it completes
successfully or TTO sets.
Read/IDENT Data NO ACK
(RIDNAK)
XBER<21> Sets if the read data of an I/O read or IDENT transaction is NO
ACKed by the XMI commander node.
Write Sequence Error (WSE) XBER<22> Sets if write data is missing or the DWMBB detects an XMI
parity error on the write data cycle.
Parity Error (PE) XBER<23> Sets if a parity error is detected during any XMI cycle, including
null cycles, for any node on the XMI, not just this DWMBB.
Inconsistent Parity Error (IPE) XBER<24> Sets if a parity error is detected during an XMI cycle that is
ACKed.
Corrected Confirmation (CC) XBER<27> Sets if a single-bit error is detected and corrected on XMI
CNF<2:0>. CC is used as a performance monitor for the system
but does not affect DWMBB performance.
Error Summary (ES) XBER<31> Sets if any of the above error bits set.
3–124