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Intel BFCBASE Data Sheet - Page 137

Checksums, 7.4.5 Scratch EEPROM, Table 7-7., Byte ROM Checksum Values

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Features Offset: 7Fh Bit Description 7:0 Feature Data Checksum One Byte Checksum of the Feature Data Section 00h- FFh: See Section 7.4.4 for calculation of the value 7.4.4 Checksums The PIROM includes multiple checksums. Table 7-7 includes the checksum values for each section defined in the 128 byte ROM. Table 7-7. 128 Byte ROM Checksum Values Section Header Processor Data Processor Core Data Cache Data Package Data Part Number Data Thermal Ref. Data Feature Data Checksum Address 0Dh 15h 24h 31h 37h 6Fh 73h 7Fh Checksums are automatically calculated and programmed by Intel. The first step in calculating the checksum is to add each byte from the field to the next subsequent byte. This result is then negated to provide the checksum. Example: For a byte string of AA445Ch, the resulting checksum will be B6h. AA = 10101010 44 = 01000100 5C = 0101100 AA + 44 + 5C = 01001010 Negate the sum: 10110101 +1 = 101101 (B6h) 7.4.5 Scratch EEPROM Also available in the memory component on the processor SMBus is an EEPROM which may be used for other data at the system or processor vendor's discretion. The data in this EEPROM, once programmed, can be write-protected by asserting the active-high SM_WP signal. This signal has a weak pull-down (10 kΩ) to allow the EEPROM to be programmed in systems with no implementation of this signal. The Scratch EEPROM resides in the upper half of the memory component (addresses 80 - FFh). The lower half comprises the Processor Information ROM (addresses 00 - 7Fh), which is permanently write-protected by Intel. § Document Number: 318080-002 137

Section	Page
1 Introduction	9
1.1 Terminology	11
1.2 State of Data	13
1.3 References	13
2 Electrical Specifications	15
2.1 Front Side Bus and GTLREF	15
2.2 Decoupling Guidelines	15
2.2.1 VCC Decoupling	16
2.2.2 VTT Decoupling	16
2.2.3 Front Side Bus AGTL+ Decoupling	16
2.3 Front Side Bus Clock (BCLK[1:0]) and Processor Clocking	16
2.3.1 Front Side Bus Frequency Select Signals (BSEL[2:0])	17
2.3.2 PLL Power Supply	17
2.4 Voltage Identification (VID)	17
2.5 Reserved, Unused, or Test Signals	20
2.6 Front Side Bus Signal Groups	20
2.7 CMOS Asynchronous and Open Drain Asynchronous Signals	22
2.8 Test Access Port (TAP) Connection	22
2.9 Mixing Processors	23
2.10 Absolute Maximum and Minimum Ratings	23
2.11 Processor DC Specifications	24
2.11.1 Flexible Motherboard Guidelines (FMB)	25
2.11.2 Platform Environmental Control Interface (PECI) DC Specifications	35
2.11.3 VCC Overshoot Specification	37
2.11.4 AGTL+ FSB Specifications	38
2.12 Front Side Bus AC Specifications	40
2.13 Processor AC Timing Waveforms	45
3 Mechanical Specifications	57
3.1 Package Mechanical Drawing	57
3.2 Processor Component Keepout Zones	60
3.3 Package Loading Specifications	66
3.4 Package Handling Guidelines	67
3.5 Package Insertion Specifications	67
3.6 Processor Mass Specifications	67
3.7 Processor Materials	67
3.8 Processor Markings	68
3.9 Processor Pin-Out Coordinates	69
4 Pin Listing	71
4.1 Pin Assignments	71
4.1.1 Pin Listing by Pin Name	71
4.1.2 Pin Listing by Pin Number	79
5 Signal Definitions	87
5.1 Signal Definitions.	87
6 Thermal Specifications	95
6.1 Package Thermal Specifications	95
6.1.1 Thermal Specifications	95
6.1.2 Thermal Metrology	102
6.2 Processor Thermal Features	103
6.2.1 Thermal Monitor Features	103
6.2.2 Thermal Monitor	103
6.2.3 Thermal Monitor 2	104
6.2.4 On-Demand Mode	105
6.2.5 PROCHOT# Signal	106
6.2.6 FORCEPR# Signal	106
6.2.7 THERMTRIP# Signal	106
6.3 Platform Environment Control Interface (PECI)	107
6.3.1 Introduction	107
6.3.2 PECI Specifications	108
7 Features	111
7.1 Power-On Configuration Options	111
7.2 Clock Control and Low Power States	111
7.2.1 Normal State	112
7.2.2 HALT or Extended HALT State	112
7.2.3 Stop-Grant State	114
7.2.4 Extended HALT Snoop or HALT Snoop State, Stop Grant Snoop State	115
7.3 Enhanced Intel SpeedStep® Technology	115
7.4 System Management Bus (SMBus) Interface	116
7.4.1 SMBus Device Addressing	117
7.4.2 PIROM and Scratch EEPROM Supported SMBus Transactions	118
7.4.3 Processor Information ROM (PIROM)	119
7.4.4 Checksums	137
7.4.5 Scratch EEPROM	137
8 Boxed Processor Specifications	139
8.1 Introduction	139
8.2 Thermal Specifications	139
8.2.1 Boxed Processor Cooling Requirements	139
9 Debug Tools Specifications	141
9.1 Debug Port System Requirements	141
9.2 Logic Analyzer Interface (LAI)	141
9.2.1 Mechanical Considerations	141