Datasheet

AT30TSE004A [DATASHEET]
Atmel-8868C-DTS-AT30TSE004A-Datasheet_122013
12
6. Temperature Sensor
6.1 Functional Description
The temperature sensor consists of a Delta-Sigma Analog to Digital Converter (ADC) with a band gap type
temperature sensor that monitors and updates its temperature measurement at least eight times per second
converting the temperature readings into digital data bits and latching them into the Temperature Register that
can be read via the 2-wire I
2
C FM+ serial interface.
The device communicates over a 2-wire I
2
C FM+ interface with a Master consisting of a Serial Clock (SCL) and
a Serial Bidirectional Data Bus (SDA) with clock frequencies up to 1MHz. The Master generates the SCL signal
and is used by the AT30TSE004A to receive and send serial data on the SDA line with the Most Significant Bit
transferred first. A pull-up resistor is required on the SDA pin since it has an open drain configuration.
6.1.1 EVENT Output
The EVENT pin has three operating modes depending on the configuration settings:
 Interrupt Mode
 Comparator Mode
 Critical Alarm (Crit_Alarm) Mode
While in Interrupt Mode, once a temperature reaches a boundary limit, the AT30TSE004A asserts the EVENT
pin. The EVENT pin will remain asserted until the system clears the interrupt by writing a Logic 1 to the EVTCLR
bit five in the Configuration Register. When the temperature drops below specified limits, the device returns
back to either Interrupt or Comparator Mode as programmed in the Configuration Register’s EVTMOD bit zero.
In Comparator Mode, the EVENT pin remains asserted until the error condition that caused the pin to be
asserted no longer exists and the EVENT pin will clear itself. In the Crit_Alarm Mode, when the measured
temperature exceeds Crit_Alarm limit, the EVENT pin will remain asserted until the temperature drops below the
Crit_Alarm limit minus hysteresis (see Figure 6-1 on page 17). All event thresholds use hysteresis as
programmed in the Configuration Register.
6.1.2 Alarm Window
The Alarm Window consists of the Upper Limit Register and Lower Limit Register. The Upper Limit Register
holds the upper temperature trip point and the Lower Limit Register holds the lower temperature trip point. After
the EVENT pin control is enabled, the EVENT output will be triggered upon entering and exiting from this
window.
6.2 Register Descriptions
This section describes all the temperature sensor registers that are used in the AT30TSE004A. The
AT30TSE004A contains several registers that are user accessible and/or programmable and utilized for latching
the temperature readings, storing high, low, and critical temperature limits, configuring the temperature sensor
performance, and reporting temperature sensor status.
These registers include a Capability Register, Configuration Register, Upper Limit Register, Lower Limit
Register, Critical Alarm Register, Temperature Register, Manufacturer Identification Register, and a Device
Identification/Device Revision Register.
The AT30TSE004A utilizes an 8-bit Pointer Register to access the 16-bit registers. Table 6-1 indicates the
Write/Read access capability for each register.
Note: Reading from a Write-only register will result in reading Logic 0 data, and writing to a Read-only register will have
no impact even though the Write sequence will be acknowledged by the device.