SE97 NXP [NXP Semiconductors], SE97 Datasheet - Page 10

• Manufacturer Part Number: SE97
• Description: DDR memory module temp sensor with integrated SPD, 3.3 V
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
SE97_5
Product data sheet
7.3.3.1 Comparator mode
7.3.3.2 Interrupt mode
7.3.3 Event operation modes
In comparator mode, the EVENT output behaves like a window-comparator output that
asserts when the temperature is outside the window (e.g., above the value programmed in
the Upper Boundary Alarm Trip register or below the value programmed in the Lower
Boundary Alarm Trip register or above the Critical Alarm Trip resister if T
selected). Reads/writes on the registers do not affect the EVENT output in comparator
mode. The EVENT signal remains asserted until the temperature goes inside the alarm
window or the window thresholds are reprogrammed so that the current temperature is
within the alarm window.
The comparator mode is useful for thermostat-type applications, such as turning on a
cooling fan or triggering a system shutdown when the temperature exceeds a safe
operating range.
In interrupt mode, EVENT asserts whenever the temperature crosses an alarm window
threshold. After such an event occurs, writing a 1 to the Clear EVENT bit (CEVNT) in the
configuration register de-asserts the EVENT output until the next trigger condition occurs.
In interrupt mode, EVENT asserts when the temperature crosses the alarm upper
boundary. If the EVENT output is cleared and the temperature continues to increase until
it crosses the critical temperature threshold, EVENT asserts again. Because the
temperature is greater than the critical temperature threshold, a Clear EVENT command
does not clear the EVENT output. Once the temperature drops below the critical
temperature, EVENT de-asserts immediately.
•
– Competitor devices: Compares the Alarm Window with temperature register at any
– Work-around: Wait at least 125 ms before enabling EVENT output (EOCTL = 1).
– SE97B will compare alarm window and temperature register immediately.
Advisory note:
– NXP device: If the EVENT output is not cleared before the temperature goes above
– Competitor devices: If the EVENT output is not cleared before or when the
time, so they get the EVENT output immediately when new T
output are set at the same time.
Intel will change Nehalem BIOS so that T
EVENT output is enabled and Event value is checked.
1. Set T
2. Doing something else (make sure that exceeds 125 ms).
3. Enable the EVENT output (EOCTL = 1).
4. Wait 20 s.
5. Read Event value.
the critical temperature threshold EVENT de-asserts immediately when
temperature drops below the critical temperature.
temperature is in the critical temperature threshold, EVENT will remain asserted
after the temperature drops below the critical temperature until a Clear EVENT
command.
th(crit)
.
Rev. 05 — 6 August 2009
DDR memory module temp sensor with integrated SPD, 3.3 V
th(crit)
is set for more than 125 ms before
th(crit)
© NXP B.V. 2009. All rights reserved.
th(crit)
and EVENT
only is
SE97
10 of 54