Intel III Xeon 800 MHz 80526KZ800256 User Manual
Product codes
80526KZ800256
PROCESSOR FEATURES
51
1.
This is an 8-bit field. The device that sent the alert will respond to the ARA Packet with its address in the seven most
significant bits. The least significant bit is undefined and may return as a ‘1’ or ‘0’. See Section 5.2.7 for details on the
Thermal Sensor Device addressing.
significant bits. The least significant bit is undefined and may return as a ‘1’ or ‘0’. See Section 5.2.7 for details on the
Thermal Sensor Device addressing.
Table 41. Command Byte Bit Assignments
Register Command
Reset
State
Function
RESERVED
00h
N/A
Reserved for future use
RRT
01h
N/A
Read processor core thermal data
RS
02h
N/A
Read status byte (flags, busy signal)
RC
03h
0000 0000
Read configuration byte
RCR
04h
0000 0010
Read conversion rate byte
RESERVED
05h
0111 1111
Reserved for future use
RESERVED
06h
1100 1001
Reserved for future use
RRHL
07h
0111 1111
Read processor core thermal diode T
HIGH
limit
RRLL
08h
1100 1001
Read processor core thermal diode T
LOW
limit
WC 09h
N/A
Write
configuration
byte
WCR 0Ah
N/A
Write
conversion
rate
byte
RESERVED
0Bh
N/A
Reserved for future use
RESERVED
0Ch
N/A
Reserved for future use
WRHL
0Dh
N/A
Write processor core thermal diode T
HIGH
limit
WRLL
0Eh
N/A
Write processor core thermal diode T
LOW
limit
OSHT
0Fh
N/A
One shot command (use send byte packet)
RESERVED
10h – FFh
N/A
Reserved for future use
All of the commands are for reading or writing registers in the thermal sensor except the one-shot command
(OSHT). The one-shot command forces the immediate start of a new conversion cycle. If a conversion is in
progress when the one-shot command is received, then the command is ignored. If the thermal sensor is in
standby mode when the one-shot command is received, a conversion is performed and the sensor returns to
standby mode. The one-shot command is not supported when the thermal sensor is in auto-convert mode.
If the thermal sensor is in auto-convert mode and is between conversions, then the conversion rate timer
resets, and the next automatic conversion takes place after a full delay elapses. The default command after
reset is to a reserved value (00h). After reset, receive byte packets will return invalid data until another
command is sent to the thermal sensor. This one-shot feature is currently susceptible to failure and should
not be used (i.e. don't issue one-shot commands) when in auto convert mode.
(OSHT). The one-shot command forces the immediate start of a new conversion cycle. If a conversion is in
progress when the one-shot command is received, then the command is ignored. If the thermal sensor is in
standby mode when the one-shot command is received, a conversion is performed and the sensor returns to
standby mode. The one-shot command is not supported when the thermal sensor is in auto-convert mode.
If the thermal sensor is in auto-convert mode and is between conversions, then the conversion rate timer
resets, and the next automatic conversion takes place after a full delay elapses. The default command after
reset is to a reserved value (00h). After reset, receive byte packets will return invalid data until another
command is sent to the thermal sensor. This one-shot feature is currently susceptible to failure and should
not be used (i.e. don't issue one-shot commands) when in auto convert mode.
5.2.6
THERMAL SENSOR REGISTERS
5.2.6.1
Thermal Reference Registers
The processor core and thermal sensor internal thermal reference registers contain the thermal reference
value of the thermal sensor and the processor core thermal diodes. This value ranges from +127 to -128
decimal and is expressed as a two’s complement, eight-bit number. These registers are saturating, i.e. values
above 127 are represented at 127 decimal, and values below -128 are represented as -128 decimal.
value of the thermal sensor and the processor core thermal diodes. This value ranges from +127 to -128
decimal and is expressed as a two’s complement, eight-bit number. These registers are saturating, i.e. values
above 127 are represented at 127 decimal, and values below -128 are represented as -128 decimal.
5.2.6.2 Thermal
Limit
Registers
The thermal sensor has two thermal limit registers; they define high and low limits for the processor core
thermal diode. The encoding for these registers is the same as for the thermal reference registers. If the diode
thermal value equals or exceeds one of its limits, then its alarm bit in the Status Register is triggered.
thermal diode. The encoding for these registers is the same as for the thermal reference registers. If the diode
thermal value equals or exceeds one of its limits, then its alarm bit in the Status Register is triggered.