Rainbow Electronics LM81 - Manual (Page 21)

Functional Description
(Continued)
Extended Repetitive Interrupt Mode is shown in Figure 14
and operates in the following way: Once activated, all inter-
rupts remain activated until reset by a read of the Interrupt
Status Register 1. Once activated all T_CRIT_A interrupts
remain activated until reset by a read of the Extended Mode
Register 1. Temperature conversion data less than or equal
to T
LOW
will activate interrupt. Interrupt will continue to be
activated until the temperature data exceeds (T
LOW
+
T
HYST
). Exceeding T
HIGH
activates interrupt. Interrupt will
continue to be activated at the end of a conversion until the
temperature data is less than or equal to (T
HIGH
− T
HYST
).
T_CRIT_A interrupts are activated when the temperature
exceeds T_CRIT. T_CRIT_A interrupts will no longer be
activated if the temperature data at the end of a conversion
is less than or equal to( T_CRIT − T
HYST
).
Extended One-Time Interrupt Mode is shown in Figure 15
and operates in the following way: Once activated all inter-
rupts remain activated until reset by a read of the Interrupt
Status Register 1. Once activated all T_CRIT_A interrupts
remain activated until reset by a read of the Extended Mode
Register 1. An interrupt will be activated when the data of a
temperature conversion is less than or equal to T
LOW
. Inter-
rupt cannot again be activated until the data from a tempera-
ture conversion is greater than (T
LOW
+ T
HYST
). An interrupt
will be activated when the data of a temperature conversion
is greater than T
HIGH
. Interrupt cannot again be activated
until the data of a temperature conversion is less than or
equal to (T
HIGH
− T
HYST
). T_CRIT_A interrupt is activated
when the data from a temperature conversion is greater than
T_CRIT. Activation of an T_CRIT_A interrupt cannot occur
until the data from a temperature conversion is less than or
equal to ( T_CRIT − T
HYST
).
Extended Comparator Mode is shown in Figure 16 and
operates in the following way: Interrupt is activated when the
data from a temperature conversion is less than or equal to
T
LOW
. Interrupt is reset when the data from a temperature
conversion exceeds (T
LOW
+ T
HIGH
). Exceeding T
HIGH
will
activate interrupt. This interrupt will be reset when data from
a temperature conversion is less than or equal to (T
HIGH
−
T
HYST
). T_CRIT_A interrupt is activated when the tempera-
ture exceeds T_CRIT. T_CRIT_A remains active until the
data from a temperature conversion is less than or equal to
(T_CRIT − T
HYST
) resets it.
DS100072-20
* Note: Interrupt resets occur only when interrupt Status Register 1 is read.
FIGURE 14. Extended Repetitive Interrupt Mode
DS100072-21
* Note: Interrupt resets occur only when interrupt Status Register 1 is read.
FIGURE 15. Extended One-Time Interrupt
DS100072-19
* Note: Interrupt resets occur only when interrupt Status Register 1 is read.
FIGURE 16. Extended Comparator Mode
LM81
www.national.com 21