ADM1034ARQZ-R7 ON Semiconductor, ADM1034ARQZ-R7 Datasheet - Page 18

• Manufacturer Part Number: ADM1034ARQZ-R7
• Description: IC THERM/FAN SPEED CTLR 16-QSOP
• Manufacturer: ON Semiconductor

Specifications of ADM1034ARQZ-R7

• 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 ~ 5.5 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 ADM1034 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.
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,
Table 14. Status Register 2 (Reg. 0x50)
Table 15. Status Register 3 (Reg. 0x51)
The ADM1034 generates an ALERT whenever an
The ALERT output on the ADM1034 can be programmed
In SMBusALERT mode, the ALERT output remains low
For SMBusALERT mode, set the ALERT configuration bit
In SMBusALERT mode, a status bit is set when a
Bit #
Bit #
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
Name
ALERT
Name
R1T
R2T
Res
Res
T%
TS
LT
TA
F1S
F2S
Res
Res
Res
Res
FA
1 = Local THERM temperature limit has
been exceeded.
1 = Remote 1 THERM temperature limit
has been exceeded.
1 = Remote 2 THERM temperature limit
has been exceeded.
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.
1 = Fan 2 has stalled.
Reserved.
Reserved.
Reserved.
Reserved.
1 = ALERT low; indicates the ALERT
line has been pulled low.
Description
Description
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18
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
HIGH LIMIT
TEMPERATURE
STATUS BIT
SMBusALERT
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
”STICKY”
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
TEMPERATURE
source.
appropriate mask bit in the interrupt mask registers
(from Reg. 0x08 to Reg. 0x0A).
LIMITS
Figure 31. Handling SMBusALERT
Outputs
TEMP BACK IN LIMIT
(STATUS BIT STAYS SET)
INTERRUPT
MASK BIT SET
(SMBusALERT REARMED)
INTERRUPT MASK BIT
(TEMP BELOW LIMIT)
CLEARED ON READ
CLEARED
CLEARED
ON READ
TIME