Specifications
I/O Port 6-53
Table 6-23 Memory Channel Write Packet Description
Figure 6-24 Mailbox Status Return Packet
Table 6-24 gives the description of the Mailbox Status Return packet.
Field Description
Clock 1, <31>
Always zero.
Clock 1, <30>
Error. Always sent as zero by the I/O port.
Clock 1, <29:16>
Are always zero.
Clock 1, <15:11>
Command field. It is always set to a code of 11110 by the I/O port to indi-
cate a Memory Channel Write packet. For this packet bit <14> is always
one.
Clock 1, <10:8>
Length field. A Memory Channel Write packet can have two possible
lengths encoded as follows:
Bits <10:8> Length
000
100
Hexword (32 bytes)
Double hexword (64 bytes) packet
Clock 1, <7:0>
Upper portion (bits <39:32>) of the TLSB address.
Clock 2, <31:0>
Lower portion (bits <31:0>) of the TLSB address.
Clock 3 through
10, <31:0>
Data longwords 0 through 7 to be written to the remote I/O bus.
Clock 11 through
18, <31:0>
Data longwords 8 through 15 to be written to the remote I/O bus. Clocks
11 through 18 are only transmitted if the length field indicates a double
hexword packet.
31 0
Return Data <31:0>
BXB-0644-93
30
0100
UPD <31:0>
UPCTL
xxxx
1*
2
3
4
* = hose cycle
Device-Specific Status <29:0>
Return Data <63:32>
Device-Specific Status <61:30>
DE
12
xxxx
xxxx