Specifications

6-52 I/O Port
Figure 6-23 Memory Channel Write Packet
Table 6-23 gives the description of the Memory Channel Write packet.
6.6.4.2 Up Hose Packet Specifications
For Up Hose packets the command field is asserted on the UPCTL<3:0>
lines (Table 6-12) instead of the first cycle of DATA<31:0> as it is with
Down Hose packets.
Mailbox Status Return
The Mailbox Status Return packet returns the status for a previously is-
sued Down Hose Mailbox Command packet.
The Mailbox Status Return packet is used by the I/O port to flow control
Mailbox Command packets. The I/O port must receive a Mailbox Status
Return packet across the Up Hose before it issues the next Mailbox Com-
mand packet across a Down Hose.
Figure 6-24 shows the Mailbox Status Return packet.
31 30 29 0
0 E Zero ADR<39:32>
LEN
BXB-0831-94
1

2

3

4

5

6

7
.
.

16

17

18
Clock cycle
Data Longword 0
Data Longword 1
Data Longword 2
Data Longword 3
Data Longword 4
Data Longword 13
Data Longword 14
Data Longword 15
DND <31:0>
Byte Aligned Address <31:0>
15 14 13 12 11 10
11110
16 7
8
.
.