lm73cimkx-1 National Semiconductor Corporation, lm73cimkx-1 Datasheet - Page 15

• Manufacturer Part Number: lm73cimkx-1
• Description: 2.7v, Sot-23, 11-to-14 Bit Digital Temperature Sensor With 2-wire Interface
• Manufacturer: National Semiconductor Corporation

2.0 LM73 Registers
2.5 T
Pointer Address 03h (R/W)
Reset State: 8000h (–256˚C)
2.6 CONTROL/STATUS REGISTER
Pointer Address 04h (R/W)
Reset State: 08h
Bits
15:5
4:0
Bits
7
6:5
4
3
2
1
0
TO_DIS
LOW
SIGN
D15
1˚C
D7
D7
LOWER-LIMIT REGISTER
Name
Lower-Limit
Temperature
Reserved
Name
Time-Out Disable
Temperature
Resolution
reserved
ALERT Pin Status
Temperature High
Flag
Temperature Low
Flag
Data Available Flag
128˚C
RES1
0.5˚C
D14
D6
D6
Description
If the measured temperature that is stored in the temperature register falls below this
user-programmable lower temperature limit, the ALERT pin will be deactivated and the T
flag in the Control/Status register will be set to 1. Two’s complement format.
Returns zeros upon read. Recommend writing zeros only in these bits.
Description
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.
Selects one of four user-programmable temperature data resolutions
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)
Always returns zero when read. Recommend customer write zero only.
Value is 0 when ALERT output is low. Value is 1 when ALERT output is high. The ALERT
output 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 T
or (3) cleared via the ARA sequence. Recommend customer write zero only.
Bit is set to 1 when the measured temperature exceeds the T
programmable T
met: (1) measured temperature no longer exceeds the programmed T
reading the Control/Status register. If the temperature is not longer above the T
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 T
Bit is set to 1 when the measured temperature falls below the T
programmable T
met: (1) measured temperature is no longer below the programmed T
reading the Control/Status register. If the temperature is no longer below the T
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 T
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.
(Continued)
0.25˚C
RES0
64˚C
D13
D5
D5
HIGH
LOW
reserved
32˚C
D12
D4
D4
register. Flag is reset to 0 when both of the following conditions are
register. Flag is reset to 0 when both of the following conditions are
LOW
15
limit.
ALRT_STAT
16˚C
D11
D3
D3
HIGH
limit.
reserved
D10
8˚C
THI
D2
D2
HIGH
LOW
limit stored in the
TLOW
4˚C
limit stored in the
D9
D1
D1
HIGH
LOW
limit and (2) upon
limit and (2) upon
LOW
HIGH
LOW
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limit, the
DAV
2˚C
limit, this
D8
D0
D0
limit,
LOW