STTS2002_11 STMICROELECTRONICS [STMicroelectronics], STTS2002_11 Datasheet - Page 22

• Manufacturer Part Number: STTS2002_11
• Description: 2.3 V memory module temperature sensor with a 2 Kb SPD EEPROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Temperature sensor registers
4.2.5
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Event output pin functionality
The STTS2002 EVENT pin is an open drain output that requires a pull-up to V
system motherboard or integrated into the master controller. EVENT has three operating
modes, depending on configuration settings and any current out-of-limit conditions. These
modes are interrupt, comparator or critical.
In interrupt mode the EVENT pin will remain asserted until it is released by writing a ‘1’ to
the “Clear Event” bit in the status register. The value to write is independent of the EVENT
polarity bit.
In comparator mode the EVENT pin will clear itself when the error condition that caused the
pin to be asserted is removed.
In the critical mode the EVENT pin will only be asserted if the measured temperature
exceeds the critical limit. Once the pin has been asserted, it will remain asserted until the
temperature drops below the critical limit minus hysteresis.
the operation of the different modes over time and temperature.
When the hysteresis bits (bits 10 and 9) are enabled, hysteresis may be used to sense
temperature movement around trigger points. For example, when using the “above alarm
window” bit (temperature register bit 14, see
3 °C, as the temperature rises, bit 14 is set (bit 14 = 1). The temperature is above the alarm
window and the temperature register contains a value that is greater than the value set in
the alarm temperature upper boundary register (see
If the temperature decreases, bit 14 will remain set until the measured temperature is less
than or equal to the value in the alarm temperature upper boundary register minus 3 °C (see
Figure 8 on page 21
Similarly, when using the “below alarm window” bit (temperature register bit 13, see
on page
alarm temperature lower boundary register (see
decreases, bit 13 will be set to '1' when the value in the temperature register is less than the
value in the alarm temperature lower boundary register minus 3 °C (see
page 21
The device will retain the previous state when entering the shutdown mode. If the device
enters the shutdown mode while the EVENT pin is low, the shutdown current will increase
due to the additional event output pull-down current.
24) will be set to '0'. The temperature is equal to or greater than the value set in the
and
Table 10 on page 21
and
Table 10 on page 21
Doc ID 15389 Rev 5
for details.
Table 12 on page
for details.
Table 17 on page
Table 16 on page
Figure 9 on page 23
24) and hysteresis is set to
26). As the temperature
26).
Figure 8 on
DD
illustrates
STTS2002
on the
Table 12