Product specifications

ProSavageDDR P4M266 – VT8751 P4 DDR SMA North Bridge
Revision 1.1, July 19, 2002 -29- Device 0 Register Descriptions
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Technologies, Inc.
Device 0 Offset 4A – SB Downlink Status (88h) ..............RO
7-4 DnCmd Max Request Depth (0=1 DnCmd) . def = 8
3-0 DnCmd Write Buffer Size (doublewords)..... def = 8
Device 0 Offset 4C-4B – SB Uplink Command (8280h).RW
15-12 UpCmd P2C Write Buffer Size (max lines).. def = 8
11-8 UpCmd P2P Write Buffer Size (max lines) .. def = 2
7-4 UpCmd Max Request Depth (0=1 UpCmd) . def = 8
3-0 Reserved ........................................ always reads 0
Device 0 Offset 4D – SB V-Link Bus Timer (44h)..........RW
7-4 Timer for Normal Priority Requests from SB
0000 Immediate
0001 1*4 VCLKs
0010 2*4 VCLKs
0011 3*4 VCLKs
0100 4*4 VCLKs............................................default
0101 5*4 VCLKs
0110 6*4 VCLKs
0111 7*4 VCLKs
1000 8*4 VCLKs
1001 16*4 VCLKs
1010 32*4 VCLKs
1011 64*4 VCLKs
11xx Own the bus for as long as there is a request
3-0 Timer for High Priority Requests from SB
0000 Immediate
0001 1*2 VCLKs
0010 2*2 VCLKs
0011 3*2 VCLKs
0100 4*2 VCLKs............................................default
0101 5*2 VCLKs
0110 6*2 VCLKs
0111 7*2 VCLKs
1000 8*2 VCLKs
1001 16*2 VCLKs
1010 32*2 VCLKs
1011 64*2 VCLKs
11xx Own the bus for as long as there is a request
Device 0 Offset 4E – CCA Master Priority (00h)........... RW
7 1394 High Priority
0 Low priority........................................... default
1 High priority
6LAN/NICHighPriority
0 Low priority........................................... default
1 High priority
5 Reserved ........................................always reads 0
4USBHighPriority
0 Low priority........................................... default
1 High priority
3 Reserved ........................................always reads 0
2IDEHighPriority
0 Low priority........................................... default
1 High priority
1 AC97-ISA High Priority
0 Low priority........................................... default
1 High priority
0 PCI High Priority
0 Low priority........................................... default
1 High priority
Device 0 Offset 4F – SB V-Link Misc Control (00h) ..... RW
7 Upstream Command High Priority
0 Disable high priority up commands....... default
1 Enable high priority up commands
6-1 Reserved ........................................always reads 0
0 Down Cycle Wait for Up Cycle Write Flush
(Except Down Cycle Post Write)
0 Disable................................................... default
1 Enable