User`s guide

DWMBB Adapter
3.12.7 VAXBI Errors
VAXBI errors originate on either a VAXBI device or the VAXBI bus. These
errors are detected by the DWMBB/B module’s BIIC and by other VAXBI
devices. Error status bits are set in the BIIC’s Bus Error Register (BER).
If a failure is detected during an I/O write transaction on the VAXBI, it
is considered a disconnected write. The DWMBB/B module informs the
DWMBB/A module that the I/O write failed, causing I/O Write Failure
(AESR<6>) to set, the I/O address to be logged in AREAR<29:0>, and an
IVINTR to be generated if enabled in AIMR.
If a failure is detected during an I/O read transaction on the VAXBI, the
DWMBB/B module informs the DWMBB/A module that the I/O read failed
and an INTR is generated if enabled.
If a VAXBI failure during a DMA write transaction is detected by the BIIC
in time for it to NO ACK the issuing VAXBI node, the DMA write is not
considered a disconnected write and no IVINTR is generated but an INTR
is generated if Interrupt on I/O Write Fail (AIMR<6>) is set. If the BIIC
does not detect the failure in time to NO ACK the transmitting node, the
DMA write is considered a disconnected write, and an IVINTR is issued by
the DWMBB/A module if IVINTRs are enabled.
If the BIIC detects a VAXBI failure during a DMA read transaction, an
INTR is generated by the DWMBB/B module and the transmitting VAXBI
node is NO ACKed.
Other VAXBI errors are handled conventionally.
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