Specifications

6-62 I/O Port
Table 6-33 Sparse Window Read Data Return Packet Description
Dense Window Read Data Return Packet
The Dense Window Read Data Return packet is used by adapters on re-
mote buses that support I/O window space packets to return data re-
quested by a previous dense window read command packet. The com-
mand field value of the Dense Window Read Data Return packet is D
(hex).
This packet is supported by the Mailbox Only, I/O Window, Full, and Mem-
ory Channel variants of the hose protocol. Figure 6-31 shows the Dense
Window Read Data Return packet.
Field Description
Clock 1, <31>
Is always zero.
Clock 1, <30>
Error. Set by the remote I/O bus adapter if any errors were detected on
the transfer.
Clock 1, <29:26>
Virtual ID of the TLSB commander node. This enables the I/O port to as-
sociate the packet with the originating commander node of the transac-
tion. This field is the same as the VID field in the Down Hose Sparse Win-
dow Read Command packet being acknowledged.
Clock 1, <25:10>
Are always zero.
Clock 1, <9:6>
Count field. Used by the I/O port to obtain the maximum number of win-
dow transactions the remote I/O bus adapter is capable of queueing. The
value in this field should always be the same for a specific remote bus I/O
adapter. The I/O port keeps track of the number of buffers that have been
filled.
NOTE: The I/O port sets the value of its remote adapter node buffer count
field to one at power-up or system initialization. The I/O port sets its re-
mote adapter node buffer count field to the value in this count field upon
receiving a sparse window read data return packet.
Clock 1, <5:0>
Are always zero.
Clocks 2 and 3,
<31:0>
Bits <31:0> are return data longword 0 and 1, respectively, of the sparse
read.