User`s guide

DWMBB/A Module Registers

Utility Register (AUTLR)

bits<13:0>

Name: VAXBI Window Space

Mnemonic: BIWIN

Type: R/W, 0

VAXBI Window Space enables software to reconﬁgure the VAXBI I/O

address space to any 32-Mbyte address range within the 512-Mbyte

I/O address space.

The base address of this window space normally depends on the XMI

node ID and the VAXBI node ID. With VAXBI Window Space Enable

(ACSR<5>) clear, the DWMBB defaults to the following equation to

determine if an I/O request is within its VAXBI I/O window space:

For 32-bit addressing:

bb = E00 000 + (200 000 * XMI Node ID) + (2000 * VAXBI Node ID)

For 30-bit addressing:

bb = 200 000 + (200 000 * XMI Node ID) + (2000 * VAXBI Node ID)

When VAXBI Window Space Enable is set, the DWMBB uses the value

loaded in the VAXBI Window Space ﬁeld to calculate the new location

for the VAXBI I/O window space, using the following equation:

For 32-bit addressing:

bb = E000 000 + (200 000 * AUTLR<13:0>) + (2000 * VAXBI Node ID)

For 30-bit addressing:

bb = 2000 000 + (200 000 * AUTLR<13:0>) + (2000 * VAXBI Node ID)

Since the use of node 0 in VAXBI window space is illegal, the value of

AUTLR<13:0> cannot be zero. Therefore, VAXBI Window Space must

be loaded before asserting VAXBI Window Space Enable.

An I/O command will be NO ACKed by the DWMBB under the

following conditions:

• The command is not targeted at a DWMBB CSR

• VAXBI Window Space Enable is asserted and VAXBI Window

Space equals zero

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