User`s guide

DWMBB Adapter
3.13 DWMBB Initialization
This section discusses the DWMBB initialization.
The four ways to reset the DWMBB are:
• Normal Power-Up—When the system is powered up, XMI AC LO L
and XMI DC LO L are sequenced so that all XMI nodes are reset.
• System Reset—The XMI emulates a power-up sequence by asserting
the XMI RESET L line, causing the power supply to sequence XMI AC
LO L and XMI DC LO L as in a "real" power-up. The XMI does not
differentiate between a "real" power-up and a system reset.
• Console INITIALIZE command—The console INITIALIZE command
generates a system reset if no argument is supplied to the command.
• Node Reset—A DWMBB is "node reset" by setting its Node Reset
(XBER<30>) bit. The differences between the node reset and a system
reset are as follows:
— XMI AC LO L is not sequenced during node reset.
— VAXBI "self-test" is not run during node reset.
When initialized, the DWMBB performs as follows:
• Any transaction currently in progress is aborted.
• All DWMBB logic resets to a known state.
• The page map registers are cleared.
• The DWMBB/B module sequences the BI AC LO and BI DC LO
signals, causing each VAXBI node to reset its logic.
A reset originating on the VAXBI by some node other than the DWMBB/B
module causes an XMI reset, allowing various VAXBI devices to remotely
boot the system.
If the DWMBB/B module and the VAXBI subsystem are powered down,
the DWMBB/A module and the XMI are unaffected. However, operations
involving the DWMBB/B module will not complete. Any attempted I/O
write transaction sets I/O Write Failure (ASER<6>), causing IVINTRs, if
enabled.
After initialization the DWMBB default operating mode is the DWMBA
compatibility mode. The following occurs during this mode:
• XMI timeouts are enabled with a default of 14–15 ms.
• DWMBB window space is determined by the node ID.
• Address translation is disabled.
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