Electrical Specifications
2-2 Intel® Itanium ™ Processor at 800 MHz and 733 MHz Datasheet
All system bus outputs should be treated as open drain and require a high level source provided
externally by the termination resistor .
AGTL+ inputs have dif ferential input b uffers which use 2/3 VCTERM as a ref erence level. AGTL+
output signals require termination to VCTERM. In this document, “AGTL+ Input Signals” refers to
the AGTL+ input group as well as the AGTL+ I/O group when receiving. Similarly, “AGTL+
Output Signals” refers to the AGTL+ output group as well as the AGTL+ I/O group when driving.
The Power Good s ignal and TAP (Test Access Port) Connection Input si gnals use a non -differ ential
receiver with levels that are similar to AGTL+. No reference voltage is required for these signals.
The TAP Connection Output signals are AGTL+ output signals.
The HSTL Clock signals are the differential clock inputs for the Intel Itanium processor. The
System Management Bus (SMBus) signals and LVTTL Power Pod signals are driven using the
3.3V CMOS logic lev e ls listed in Table 2-8 and Table 2-9, respectively. Please refer to
Section 2.2.2 for de scriptions for the “Other” and “Reserved” signals.
Please refer to the Intel® Itanium™ Processor Hardware Developer’s Manual for recommended
terminations for all system bus sig nals .
2.2.2 Signal Descriptions
The Intel® Itanium™ Processor Hardware Developer’s Manual document cont ains functional
descriptions of all system bus signals and LVTTL Powerpod signals. Further descriptions of the
System Management signals are contained in Chapter 6. The signals listed under the group
“Power” and “Other” are described here.
Table 2-1. Inte l® Itanium™ Processor System Bus Signal Groups
Group Name Signals
AGTL+ Input Signals BPRI#, BR[3:1]#, DEFER#, GSEQ#, ID[7:0]#, IDS#,
RESET#, RS[2:0]#, RSP#, TRDY#
AGTL+ Asynchronous Interrupt Input Signalsa
a. The AGTL+ asynchronous interrupt signals have special setup and hold timings that differ from those of standard AGTL+. See
Table 2-12 for more information.
A20M#, DRATE#, IGNNE#, INIT#, LINT[1,0], PMI#,
TRISTATE#
AGTL+ Output Signals FERR#, THERM TRIP#
AGTL+ I/O Signals A[43:3]#, ADS#, AP[1:0]#, BERR#, BINIT#, BNR#,
BPM[5:0]#, BR0#, D[63:0]#, DBSY#, DEP[7:0]#,
DRDY#, HIT#, HITM#, LOCK#, REQ[4:0]#, RP#,
SBSY#, STBN[3:0]#, STBP[3:0]#, TND#
Power Good Signal PWRGOOD
HSTL Clock Signals BCLKN, BCLKP
TAP Connection Input Signals TCK, TDI, TMS, TRST#
TAP Connection Output Signals TDO
System Management Signals 3.3V, SMA[2:0], SMSC, SMSD, SMWP,
THRMALERT#
Power Signals GND, VCTERM, VREFA[1:0], VREFC[1:0],
VREFDL[1:0], VREFDR[1:0]
LVTTL Power Pod Signals OUTEN, PPODGD#
Other TUNER[2:1], PROCPRES#
Reserved N/C , PD[3:0 ], P U [2:0]