LM73
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SNIS141F –OCTOBER 2005–REVISED OCTOBER 2015
7.5.1.6 Control/Status Register
Pointer Address 04h (R/W)
Reset State: 08h
D7 D6 D5 D4 D3 D2 D1 D0
TO_DIS RES1 RES0 reserved ALRT_STAT THI TLOW DAV
BITS NAME DESCRIPTION
7 Time-Out Disable Disable the time-out feature on the SMBDAT and SMBCLK lines if set to 1. Setting this bit turns off the
bus-idle timers, enabling the LM73 to operate at lowest shutdown current.
6:5 Temperature Selects one of four user-programmable temperature data resolutions
Resolution 00: 0.25°C/LSB, 11-bit word (10 bits plus Sign)
01: 0.125°C/LSB, 12-bit word (11 bits plus Sign)
10: 0.0625°C/LSB, 13-bit word (12 bits plus Sign)
11: 0.03125°C/LSB, 14-bit word (13 bits plus Sign)
4 reserved Always returns zero when read. Recommend customer write zero only.
3 ALERT Pin Status Value is 0 when ALERT output pin is low. Value is 1 when ALERT output pin is high. The ALERT output
pin is reset under any of the following conditions: (1) Cleared by writing a 1 to the ALERT Reset bit in the
configuration register, (2) Measured temperature falls below the TLOW limit, or (3) cleared via the ARA
sequence. Recommend customer write zero only.
2 Temperature High Flag Bit is set to 1 when the measured temperature exceeds the THIGH limit stored in the programmable THIGH
register. Flag is reset to 0 when both of the following conditions are met: (1) measured temperature no
longer exceeds the programmed THIGH limit and (2) upon reading the Control/Status register. If the
temperature is not longer above the THIGH limit, this status bit remains set until it is read by the master so
that the system can check the history of what caused the ALERT output to go active. This bit is not
cleared after every read if the measured temperature is still above the THIGH limit.
1 Temperature Low Flag Bit is set to 1 when the measured temperature falls below the TLOW limit stored in the programmable
TLOW register. Flag is reset to 0 when both of the following conditions are met: (1) measured temperature
is no longer below the programmed TLOW limit and (2) upon reading the Control/Status register. If the
temperature is no longer below the TLOW limit, the status bit remains set until it is read by the master so
that the system can check the history of what cause the ALERT output to go active. This bit is not cleared
after every read if temperature is still below TLOW limit.
0 Data Available Flag This bit is 0 when the LM73 is in the process of converting a new temperature. It is 1 when the
conversion is done. After initiating a temperature conversion while operating in the one-shot mode, this
status bit can be monitored to indicate when the conversion is done. After triggering the one-shot
conversion, the data in the temperature register is invalid until this bit is high (that is, after completion of
the conversion). On power-up, the LM73 is in continuous conversion mode; while in continuous
conversion mode (the default mode after power-on reset) this bit will always be high. Recommend
customer write zero only.
7.5.1.7 Identification Register
Pointer Address 07h (Read Only)
Reset State: 0190h
D15 D14 D13 D12 D11 D10 D9 D8
00000001
D7 D6 D5 D4 D3 D2 D1 D0
10010000
BITS NAME DESCRIPTION
15:8 Manufacturer Always returns 01h to uniquely identify the manufacturer as Texas Instruments.
Identification Byte
7:4 Product Identification Always returns 9h to uniquely identify this part as the LM73 Temperature Sensor.
Nibble
3:0 Die Revision Step Always returns 0h to uniquely identify the revision as level zero.
Nibble
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