ADM1033ARQZ-REEL7 ON Semiconductor, ADM1033ARQZ-REEL7 Datasheet - Page 17

• Manufacturer Part Number: ADM1033ARQZ-REEL7
• Description: IC THERM/FAN SPEED CTRLR 16-QSOP
• Manufacturer: ON Semiconductor

Specifications of ADM1033ARQZ-REEL7

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ALERT Interrupt Behavior
out−of−limit measurement is made (if it is not masked out).
The user can also detect out−of−limit conditions by polling
the ADM1033 status registers. It is important to note how
the SMBus ALERT output behaves when writing interrupt
handler software.
to operate in either SMBusALERT mode or in comp mode.
until the measurement falls back within its programmed
limits and either the status register is read or an ARA is
completed. In comp mode, the ALERT output automatically
resets once the temperature measurement falls back within
the programmed limits.
Configuring the ALERT Output
(Bit 3) of the Configuration Register 1 (Address 0x01) to 0.
Table 14. Status Register 2 (Reg. 0x50)
Table 15. Status Register 3 (Reg. 0x51)
The ADM1033 generates an ALERT whenever an
The ALERT output on the ADM1033 can be programmed
In SMBusALERT mode, the ALERT output remains low
For SMBusALERT mode, set the ALERT configuration bit
Bit #
Bit #
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
Unused
ALERT
Name
Name
R1T
F1S
Res
Res
Res
Res
Res
Res
Res
T%
TS
FA
LT
TA
1 = Local THERM temperature limit has
been exceeded.
1 = Remote 1 THERM temperature limit
has been exceeded.
Reserved.
1 = THERM % on−time limit has been
exceeded.
1 = One of the THERM limits has been
exceeded; and the THERM output
signal has been asserted.
1 = THERM state. Indicates the THERM
pin is active; clears on a read if THERM
is not active. Does not generate an
ALERT in ALERT comp mode.
Reserved.
Reserved.
1 = Fan 1 has stalled.
1 = Fan alarm speed. Fan1 and Fan 2
are running at alarm speed.
Reserved.
Reserved.
Reserved.
Reserved.
Reserved.
1 = ALERT low; indicates the ALERT
line has been pulled low.
Description
Description
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17
measurement goes outside of its programmed limit. If the
corresponding mask bit is not set, the ALERT output is
pulled low. If the measured value falls back within the limits,
the ALERT output remains low until the corresponding
status register is read or until an ARA is completed (as long
as no other measurement is outside its limits).
of Configuration Register 1 (Address 0x01) to1.
low when a measurement goes outside its programmed limits.
Once the measurement falls back within its limits (and
assuming no other measurement channel is outside its limits),
the ALERT output is automatically pulled high again.
SMBusALERT does not reset without software intervention,
whereas the comp mode ALERT output automatically resets.
Handling SMBusALERT Interrupts
steps:
ALERT, 70°C
ALERT COMP
SMBusALERT
In SMBusALERT mode, a status bit is set when a
For comp mode, set the ALERT configuration bit (Bit 3)
In comp mode, the ALERT output is automatically pulled
The main difference between the two modes is that the
To prevent tie−ups due to service interrupts, follow these
Figure 30. ALERT Comparator and SMBusALERT
1. Detect an SMBus assertion.
2. Enter the interrupt handler.
3. Read the status register to identify the interrupt
4. Mask the interrupt source by setting the
5. Take the appropriate action for a given interrupt
6. Exit the interrupt handler.
7. Periodically poll the status register. If the interrupt
TEMPERATURE
source.
appropriate mask bit in the interrupt mask registers
(from Reg. 0x08 to Reg. 0x0A).
source.
status bit clears, reset the corresponding interrupt
mask bit to 0. The SMBusALERT output and
status bits then behave as shown in Figure 31.
LIMITS
Outputs
CLEARED
ON READ
TIME