|NE1617A(2009)||Temperature monitor for microprocessor systems|
|NE1617A Datasheet PDF : 27 Pages |
Temperature monitor for microprocessor systems
8.3.1 Low power standby modes
Upon POR, the device is reset to its normal free-running auto-conversion operation mode.
The device can be put into standby mode by either using hardware control (connect the
STBY pin to LOW for hardware standby mode) or using software control (set bit 6 of the
conﬁguration register to HIGH for software standby mode). When the device is put in
either one of the standby modes, the supply current is reduced to less than 10 µA if there
is no SMBus activity, all data in the device registers are retained and the SMBus interface
is still alive to bus communication. However, there is a difference in the device ADC
conversion operation between hardware standby and software standby modes. In
hardware standby mode, the device conversion is inhibited and the one-shot command
does not initiate a conversion. In software standby mode, the one-shot command will
initiate a conversion for both internal and external channels.
If a hardware standby command is received when the device is in normal mode and a
conversion is in progress, the conversion cycle will stop and data in reading temperature
registers will not be updated.
8.3.2 Conﬁguration register
The conﬁguration register is used to mask the Alert interrupt and/or to put the device in
software standby mode. Only two bits of this register (bit 6 and bit 7) are used as listed in
Table 5. Bit 7 is used to mask the device ALERT output from Alert interruption when this
bit is set to logic 1, and bit 6 is used to activate the standby software mode when this bit is
set to logic 1.
This register can be written or read using the commands of registers named WC and RC
accordingly. Upon Power-On Reset (POR), both bits are reset to zero.
5 to 0
Conﬁguration register bit assignments
Symbol POR state Function
Mask ALERT interrupt. Interrupt is enabled when this bit
is LOW, and disabled when this bit is HIGH.
Standby or run mode control. When LOW, running mode
is enabled; when HIGH, standby mode is initiated.
8.3.3 External and internal temperature registers
Results of temperature measurements after every ADC conversion are stored in two
registers: Internal Temp register (RIT) for internal or local diode temperature, and External
Temp register (RET) for external or remote diode temperature. These registers can be
only read over the SMBus. The reading temperature data is in 2's complement binary form
consisting of 7-bit data and 1-bit sign (MSB), with each data count represents 1 °C, and
the MSB bit is transmitted ﬁrst over the serial bus. The contents of those two registers are
updated upon completion of each ADC conversion. Table 6 shows some values of the
temperature and data.
Product data sheet
Rev. 04 — 30 July 2009
© NXP B.V. 2009. All rights reserved.
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