Datasheet

TMP411-Q1
SBOS527F –DECEMBER 2010–REVISED NOVEMBER 2013 www.ti.com
STATUS REGISTER
The RHIGH bit reads as 1 if the remote temperature
has exceeded the remote high limit and remains
The TMP411-Q1 has a Status Register to report the
greater than the remote high limit less the value in
state of the temperature comparators. Table 5 shows
the Hysteresis Register. The LLOW and RLOW bits
the Status Register bits. The Status Register is read-
are not affected by the AL/TH bit.
only and is read by reading from pointer address 02h.
The LLOW bit reads as 1 if the local low limit was
The BUSY bit reads as 1 if the ADC is making a
exceeded since the last clearing of the Status
conversion. It reads as 0 if the ADC is not converting.
Register. The RLOW bit reads as 1 if the remote low
The OPEN bit reads as 1 if the remote transistor was limit was exceeded since the last clearing of the
detected as open since the last read of the Status Status Register.
Register. The OPEN status is only detected when the
The values of the LLOW, RLOW, and OPEN (as well
ADC is attempting to convert a remote temperature.
as LHIGH and RHIGH when AL/TH is 0) are latched
The RTHRM bit reads as 1 if the remote temperature and read as 1 until the Status Register is read or a
has exceeded the remote THERM limit and remains device reset occurs. These bits are cleared by
greater than the remote THERM limit less the value in reading the Status Register, provided that the
the shared Hysteresis Register; see Figure 18. condition causing the flag to be set no longer exists.
The values of BUSY, LTHRM, and RTHRM (as well
The LTHRM bit reads as 1 if the local temperature
as LHIGH and RHIGH when ALERT/THERM2 is 1)
has exceeded the local THERM limit and remains
are not latched and are not cleared by reading the
greater than the local THERM limit less the value in
Status Register. They always indicate the current
the shared Hysteresis Register; see Figure 18.
state, and are updated appropriately at the end of the
corresponding ADC conversion. Clearing the Status
The LHIGH and RHIGH bit values depend on the
Register bits does not clear the state of the ALERT
state of the AL/TH bit in the Configuration Register. If
pin; an SMBus alert response address command
the AL/TH bit is 0, the LHIGH bit reads as 1 if the
must be used to clear the ALERT pin.
local high limit was exceeded since the last clearing
of the Status Register. The RHIGH bit reads as 1 if
The TMP411-Q1 NORs LHIGH, LLOW, RHIGH,
the remote high limit was exceeded since the last
RLOW, and OPEN, so a status change for any of
clearing of the Status Register. If the AL/TH bit is 1,
these flags from 0 to 1 automatically causes the
the remote high limit and the local high limit are used
ALERT pin to go low (only applies when the
to implement a THERM2 function. LHIGH reads as 1
ALERT/THERM2 pin is configured for ALERT mode).
if the local temperature has exceeded the local high
limit and remains greater than the local high limit less
the value in the Hysteresis Register.
Table 5. Status Register Format
STATUS REGISTER (Read = 02h, Write = NA)
BIT # D7 D6 D5 D4 D3 D2 D1 D0
BIT NAME BUSY LHIGH LLOW RHIGH RLOW OPEN RTHRM LTHRM
POR VALUE 0
(1)
0 0 0 0 0 0 0
(1) The BUSY bit changes to 1 almost immediately (<<100 μs) following power up, as the TMP411-Q1 begins the first temperature
conversion. The BUSY bit is high whenever the TMP411-Q1 is converting a temperature reading.
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