Datasheet

10 Atmel AT30TS00 [Preliminary]
8585B−SEEPR−8/10
5.3. Temperature Sensor Power-on Default
The Atmel
®
AT30TS00 has an internal Power-on Reset (POR) circuit. When the supply voltage drops below the
POR threshold, the device will reset to the following power-on default conditions:
• Sensor starts monitoring temperature continuously
• Address Pointer Register = 00h
• Upper / Lower Alarm Trip registers and Crit_Alarm registers are set to 0°C
•
EVENT
register cleared and pulled high by external pull up resistor
• Operational mode is Comparator
•
EVENT
hysteresis is 0°C
• SMBus register =00h
5.4. Device Initialization
The AT30TS00 Temperature Sensor has programmable registers that, upon device power-on, are initialized to ‘0’.
Table 6-1 shows the power-on register default values. The
EVENT
output is defaulted to deasserted state and
comparator mode. Please note the Upper Alarm Trip, Lower Alarm Trip, Critical Alarm Trip registers and
Configuration registers need to be programmed to the desired values before temperature sensor can properly
function.
5.5. SMBus Timeout
The AT30TS00 supports the SMBus timeout feature if enabled via setting the SMBus register. (see Section 6.10)
This feature helps prevent potential system bus hang-ups by resetting the serial interface if SCL stays low for a
time specified by the t
OUT
parameter. This requires a minimum SCL clock speed of 10Khz as specified in the
SMBus specification to avoid any timeout issues.