ADM1026JST-REEL 查看數據表（PDF） - Analog Devices
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ADM1026JST-REEL Datasheet PDF : 56 Pages
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ADM1026
ADM1026 Interrupt Structure
The Interrupt Structure of the ADM1026 is shown in Figure 53.
Interrupts can come from a number of sources, which are com-
bined to form a common INT output. When INT is asserted,
this output pulls low. The INT pin has an internal, 100 kΩ
pull-up resistor.
Analog/Temperature Inputs
As each analog measurement value is obtained and stored in the
appropriate value register, the value and the limits from the
corresponding limit registers are fed to the high and low limit
comparators. The device performs greater than comparisons to
the high limits. An out-of-limit is also generated if a result is
less than or equal to a low limit. The result of each comparison
(1 = out of limit, 0 = in limit) is routed to the corresponding
bit input of Interrupt Status Register 1, 2, or 4 via a data
demultiplexer, and used to set that bit high or low as appro-
priate. Status bits are self-clearing. If a bit in a status register is
set due to an out-of-limit measurement, it continues to cause
INT to be asserted as long as it remains set, as described later.
However, if a subsequent measurement is in limit, it is reset and
does not cause INT to be reasserted. Status bits are unaffected
by clearing the interrupt.
Interrupt Mask Registers 1, 2, and 4 have bits corresponding to
each of the interrupt status register bits. Setting an interrupt
mask bit high conceals an asserted status bit from display on
Interrupt Pin 17. Setting an interrupt mask bit low allows the
corresponding status bit to be asserted and displayed on Pin 17.
After mask gating, the status bits are all OR’ed together to
produce the analog and fan interrupt that is used to set a latch.
The output of this latch is OR’ed with other interrupt sources to
produce the INT output. This pulls low if any unmasked status
bit goes high, that is, when any measured value goes out of limit.
When an INT output caused by an out-of-limit analog/
temperature measurement is cleared by one of the methods
described later, the latch is reset. It is not set again, and INT is
not reasserted until after two local temperature measure-ments
have been taken, even if the status bit remains set or a new
analog/temperature event occurs, as shown in Figure 50. This
delay corresponds to almost two monitoring cycles, and is about
530 ms. However, interrupts from other sources such as a fan or
GPIO can still occur. This is illustrated in Figure 51.
START OF ANALOG
MONITORING
OUT-OF-LIMIT
CYCLE
MEASUREMENT
INT CLEARED
LOCAL
TEMPERATURE
MEASUREMENT
START OF ANALOG
MONITORING
CYCLE
OUT-OF-LIMIT
MEASUREMENT
LOCAL
TEMPERATURE
MEASUREMENT
START OF ANALOG
MONITORING
CYCLE
INT
INT RE-ASSERTED
FULL MONITORING CYCLE = 273ms
Figure 50. Delay After Clearing INT Before Reassertion
START OF ANALOG OUT-OF-LIMIT LOCAL TEMPEREATURE START OF ANALOG
MONITORING CYCLE MEASUREMENT MEASUREMENT
MONITORING CYCLE
LOCAL TEMPERATURE START OF ANALOG
MEASUREMENT MONITORING CYCLE
INT
INT
CLEARED CLEARED
GPIO DE-ASSERTED
INT
INT RE-ASSERTED
NEW INT
FROM FAN
NEW INT
FROM GPIO
Figure 51. Other Interrupt Sources Can Reassert INT Immediately
Rev. A | Page 28 of 56
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