Datasheet

11
Atmel AT30TSE002B [DATASHEET]
8711G–SEEPR–5/12
9. EEPROM Write Protection
The device supports permanent and reversible software write protection and once enabled, write protects the first-half of
the array (00H - 7FH).
Permanent Software Write Protection: The software write protection is enabled by sending a command similar to a
normal write command; to the device which programs the permanent write protect register. The write protect register is
programmed by sending a write command with the device address of ‘0110’ with the address and data bit being don’t
cares (see Figure 12-5 and Table 12-1). Once the software write protection has been enabled, the device will no longer
acknowledge the ‘0110’ control byte. The software write protection cannot be reversed even if the device is powered
down. The write cycle time must be observed.
Reversible Software Write Protection: The reversible software write protection is enabled by sending a command,
similar to a normal write command; to the device which programs the reversible write protect register. The write protect
register is programmed by sending a write command ‘01100010’ with pins A
2
and A
1
tied to ground or no connect and pin
A
0
connected to V
HV
(see Figure 12-6 and Table 12-1). The reversible write protection can be reversed by sending a
command ‘01100110’ with pin A
2
tied to ground or no connect, pin A
1
tied to V
CC
and pin A
0
tied to V
HV
(see Figure 12-6
and Table 12-1).
10. Temperature Sensor Functional Description
AT30TSE002B consists of a Delta-Sigma Analog to Digital Converter (ADC) with a band gap type temperature sensor
that monitors and updates its own temperature reading at least eight times per second converting the readings into digital
data bits and latching them into a temperature register that can be read via 2-wire I
2
C/SMBus serial interface. The device
communicates over a 2-wire I
2
C/SMBus interface with the bus master or controller consisting of a serial clock (SCL) and
serial bidirectional data bus (SDA) with clock frequencies up to 400Khz. The bus master or controller generates the SCL
signal and is used by the AT30TSE002B 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.
10.1 EVENT Output
The EVENT pin has three operating modes depending on configuration settings. They are Interrupt, Comparator, and
Critical Alarm (Crit_Alarm) modes.
In the Interrupt mode, once a temperature reaches a boundary limit, the AT30TSE002B asserts the
EVENT pin. The
EVENT pin will remain asserted until software clears the interrupt by writing a one 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 the 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 trip limit, the
EVENT pin will remain asserted until the temperature drops below Crit_Alarm limit minus
hysteresis (See Figure 11-1). All event thresholds use hysteresis as programmed in the configuration register.
10.2 Alarm Window
The alarm window consists of the Upper Alarm Trip Register and Lower Alarm Trip Register. The Upper Alarm Trip
Register holds the upper temperature trip point and the Lower Alarm Trip 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.