User`s guide

DWMBB Adapter
3.4.4.4 Interprocessor-Generated VAXBI Interrupts
The DWMBB/B module receives interprocessor interrupts and translates
them into generic interrupts if the BIIC is enabled for this function. The
generic interrupt is passed onto the XMI with an IPL of 16 (hex).
3.4.4.5 Passive Release of VAXBI Interrupts
If the requesting VAXBI node aborts its interrupt request before the XMI
commander generates an IDENT transaction at that level, the resulting
IDENT on the VAXBI gets NO ACKed. The DWMBB then issues the
contents of the Return Vector Register (ARVR) to the XMI commander if
Return Vector Disable (ACSR<1>) is not asserted.
If Return Vector Disable is asserted, the DWMBB issues a Read Error
Response (RER) instead of the contents of ARVR to the XMI commander.
See Section 3.4.6 for information on the return vector disable option.
3.4.5 IDENT Transactions
When an XMI commander issues an XMI IDENT to the DWMBB, the
DWMBB issues a VAXBI IDENT, providing that the DWMBB does
not have a pending interrupt at that IDENT level. DWMBB-internal
interrupts occur only at VAXBI level 7. When the DWMBB/B module
fetches the IDENT command for the DWMBB/A module, it issues the
IDENT on the VAXBI, and the VAXBI interrupt request is cleared.
When a vector is received from the VAXBI, the DWMBB generates the
proper vector for the type of transaction that caused the interrupt and
the interrupt source. It passes the vector to the DWMBB/A module, and
the DWMBB/A module transmits the vector on XMI D<15:2> during the
IDENT cycle.
If the DWMBB has a VAXBI level 7 interrupt pending when an XMI
IDENT is accepted by the DWMBB/B module, the interrupt vector for
the DWMBB is issued to the XMI, and the DWMBB interrupt request
is cleared. The IDENT does not affect the VAXBI interrupt request, if
pending at the same IPL. Another IDENT transaction is issued by an XMI
processor to service the VAXBI interrupt request.
3.4.6 Return Vector Disable Option
If Return Vector Disable (Control and Status Register (ACSR) bit <1>) is
not set, the DWMBB returns the value loaded in the DWMBB/A module’s
Return Vector Register (ARVR) whenever an unsolicited IDENT is received
by the DWMBB or a failed IDENT vector is detected by the DWMBB. The
IDENT vector that is returned to the XMI is contained in the ARVR.
The DWMBB returns an RER to the XMI if an unsolicited IDENT is
received and Return Vector Disable is set. Return Vector Disable clears on
an XMI power-up or node reset.
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