Electrical Specifications
26 Datasheet
2.6.3.1 GTL+ Front Side Bus Specifications
In most cases, termination resistors are not required as these are integrated into the
processor silicon. See Table 8 for details on which GTL+ signals do not include on-die
termination.
Valid high and low levels are determined by the input buffers by comparing with a
reference voltage called GTLREF. Table 14 lists the GTLREF specifications. The GTL+
reference voltage (GTLREF) should be generated on the system board using high
precision voltage divider circuits.
2.7 Clock Specifications
2.7.1 Front Side Bus Clock (BCLK[1:0]) and Processor Clocking
BCLK[1:0] directly controls the FSB interface speed as well as the core frequency of the
processor. As in previous generation processors, the processor’s core frequency is a
multiple of the BCLK[1:0] frequency. The processor bus ratio multiplier will be set at its
default ratio during manufacturing.
The processor uses a differential clocking implementation. For more information on the
processor clocking, contact your Intel field representative.
Table 14. GTL+ Bus Voltage Definitions
Symbol Parameter Min Typ Max Units Notes
1
NOTES:
1. Unless otherwise noted, all specifications in this table apply to all processor frequencies.
GTLREF_PU GTLREF pull-up resistor 124 * 0.99 124 124 * 1.01 Ω
2
2. GTLREF is to be generated from V
TT
by a voltage divider of 1% resistors (one divider for each
GTLEREF land). Refer to the applicable platform design guide for implementation details.
GTLREF_PD GTLREF pull-down resistor 210 * 0.99 210 210 * 1.01 Ω
2
R
TT
Termination Resistance 45 50 55 Ω
3
3. R
TT
is the on-die termination resistance measured at V
TT
/3 of the GTL+ output driver.
COMP[3:0] COMP Resistance 49.40 49.90 50.40 Ω
4
4. COMP resistance must be provided on the system board with 1% resistors. COMP[3:0] and
COMP8 resistors are to V
SS
.
COMP8 COMP Resistance 24.65 24.90 25.15 Ω
4
Table 15. Core Frequency to FSB Multiplier Configuration
Multiplication of System
Core Frequency to FSB
Frequency
Core Frequency
(266 MHz BCLK/
1066 MHz FSB)
Core Frequency
(333 MHz BCLK/
1333 MHz FSB)
Notes
1, 2
NOTES:
1. Individual processors operate only at or below the rated frequency.
2. Listed frequencies are not necessarily committed production frequencies.
1/6 1.60 GHz 2.00 GHz -
1/7 1.87 GHz 2.33 GHz -
1/8 2.13 GHz 2.66 GHz -
1/9 2.40 GHz 3.00 GHz -
1/10 2.66 GHz 3.33 GHz -
1/11 2.93 GHz 3.66 GHz -
1/12 3.20 GHz 4.00 GHz -
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