Design Guide
53
System Bus Routing Guidelines
System Bus Routing Guidelines
5
This section covers the system bus source synchronous (data, address, and associated strobes) and
common clock signal routing.
lists the signals and their corresponding signal types.
NOTES:
1. These signals do not have on-die termination on the processor. They must be terminated properly on the
motherboard. If the signal is not connected, it must be pulled to the appropriate voltage level through a
1 k
Ω
± 5%
resistor.
2. Xeon processors use only BR0# and BR1#.
3. These signals are ‘wired-OR’ signals and may be driven simultaneously by multiple agents. For further details
on how to implement wired-OR signals, refer to the routing guidelines in
4. The value of these pins during the active edge of RESET# determine processor configuration options.
5. SM_VCC has critical power sequencing requirements.
6. Terminations and routing for TAP signals and all debug port signals are found in the
ITP700 Debug Port
Design Guide
.
Table 5-1. System Bus Signal Groups
Signal Group
Type
Signals
AGTL+ Common Clock Input
Synchronous to BCLK
BPRI#, BR[3:1]#
1,2
, DEFER#,
RESET#
1
, RS[2:0]#, RSP#,
TRDY#
AGTL+ Common Clock I/O
Synchronous to BCLK
ADS#, AP[1:0]#, BINIT#
3
, BNR#
3
,
BPM[5:0]#
1
, BR0#
1
, DBSY#,
DP[3:0]#, DRDY#, HIT#
3
, HITM#
3
,
LOCK#, MCERR#
3
AGTL+ Source Synchronous I/O: 4X
Group
Synchronous to assoc. strobe
D[63:0]#, DBI[3:0]#
AGTL+ Source Synchronous I/O: 2X
Group
Synchronous to assoc. strobe
A[35:3]#
4
, REQ[4:0]#
AGTL+ Strobes
Synchronous to BCLK [1:0]
ADSTB[1:0]#, DSTBN[3:0]#,
DSTBP[3:0]#
Async GTL+ Input
1
Asynchronous
A20M#, IGNNE#, INIT#
4
, LINT0/
INTR, LINT1/ NMI, PWRGOOD,
SMI#
4
, CPUSLP#, STPCLK#
Async GTL+ Output
1
Asynchronous
FERR#, IERR#, PROCHOT#,
THERMTRIP#
System Bus Clock
Clock
BCLK0, BCLK1
TAP Input
6
Synchronous to TCK
TCK, TDI, TMS, TRST#
TAP Output
6
Synchronous to TCK
TDO
SMBus Interface
1
Synchronous to SM_CLK
SM_EP_A[2:0], SM_TS_A[1:0],
SM_DAT, SM_CLK, SM_ALERT#,
SM_WP
Power/Other
Power/Other
GTLREF[3:0], COMP[1:0], ODTEN,
RESERVED, SKTOCC#,
TESTHI[6:0], VID[4:0], VCC_CPU,
SM_VCC
5
, VCCA, VSSA,
VCCIOPLL, VSS, VCCSENSE,
VSSSENSE
Summary of Contents for Xeon
Page 24: ...Introduction 24 Design Guide This page is intentionally left blank ...
Page 30: ...Component Quadrant Layout 30 Design Guide This page is intentionally left blank ...
Page 52: ...Platform Clock Routing Guidelines 52 Design Guide This page is intentionally left blank ...
Page 66: ...System Bus Routing Guidelines 66 Design Guide This page is intentionally left blank ...
Page 118: ...Intel 82870P2 P64H2 118 Design Guide This page is intentionally left blank ...
Page 146: ...I O Controller Hub 146 Design Guide This page is intentionally left blank ...
Page 148: ...Debug Port 148 Design Guide This page is intentionally left blank ...
Page 210: ...Schematic Checklist 210 Design Guide This page is intentionally left blank ...
Page 220: ...Layout Checklist 220 Design Guide This page is intentionally left blank ...
Page 222: ...Schematics 222 Design Guide This page is intentionally left blank ...