Datasheet

TMP431
TMP432
www.ti.com SBOS441F –SEPTEMBER 2009–REVISED AUGUST 2013
Status Registers
TMP431 Status Register
Table 5. TMP431 Status Register Format
TMP431 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 (<< 100μs) following power-up, as the TMP431 begins the first temperature conversion.
It is high whenever the TMP431 is converting a temperature reading.
space
The TMP431 has a Status Register to report the state
The RHIGH bit reads as ‘1’ if the remote temperature
of the temperature comparators. Table 5 shows the
has exceeded the remote high limit and remains
Status Register bits. The Status Register is read-only
greater than the remote high limit less the value in
and is read by reading from pointer address 02h.
the Hysteresis Register.
The BUSY bit reads as ‘1’ if the ADC is making a
The LLOW and RLOW bits are not affected by the
conversion. It reads as ‘0’ if the ADC is not
AL/TH bit. The LLOW bit reads as ‘1’ if the local low
converting.
limit was exceeded since the last clearing of the
The OPEN bit reads as ‘1’ if the remote transistor Status Register. The RLOW bit reads as ‘1’ if the
was detected as open since the last read of the remote low limit was exceeded since the last clearing
Status Register. The OPEN status is only detected of the Status Register.
when the ADC is attempting to convert a remote
The values of the LLOW, RLOW, and OPEN (as well
temperature.
as LHIGH and RHIGH when AL/TH is ‘0’) are latched
The RTHRM bit reads as ‘1’ if the remote and read as ‘1’ until the Status Register is read or a
temperature exceeds the remote THERM limit and device reset occurs. These bits are cleared by
remains greater than the remote THERM limit less reading the Status Register, provided that the
the value in the shared Hysteresis Register; see condition causing the flag to be set no longer exists.
Figure 23. The values of BUSY, LTHRM, and RTHRM (as well
as LHIGH and RHIGH when ALERT/THERM2 is ‘1’)
The LTHRM bit reads as ‘1’ if the local temperature
are not latched and are not cleared by reading the
exceeds the local THERM limit and remains greater
Status Register. They always indicate the current
than the local THERM limit less the value in the
state, and are updated appropriately at the end of the
shared Hysteresis Register; see Figure 23.
corresponding ADC conversion. Clearing the Status
Register bits does not clear the state of the ALERT
The LHIGH and RHIGH bit values depend on the
pin; an SMBus alert response address command
state of the AL/TH bit in the Configuration Register 1.
must be used to clear the ALERT pin.
If the AL/TH bit is ‘0’, the LHIGH bit reads as ‘1’ if the
local high limit was exceeded since the last clearing
The TMP431 NORs LHIGH, LLOW, RHIGH, RLOW,
of the Status Register. The RHIGH bit reads as ‘1’ if
and OPEN, so a status change for any of these flags
the remote high limit was exceeded since the last
from ‘0’ to ‘1’ automatically causes the ALERT pin to
clearing of the Status Register. If the AL/TH bit is ‘1’,
go low (only applies when the ALERT/THERM2 pin is
the remote high limit and the local high limit are used
configured for ALERT mode).
to implement a THERM2 function. LHIGH reads as ‘1’
if the local temperature exceeds the local high limit
and remains greater than the local high limit less the
value in the Hysteresis Register.
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