NE1617ADS,112 Datasheet NE1617ADS,112, NE1617ADS,118 | P7-P9

Product data sheet Rev. 5 — 20 March 2012 7 of 30

NXP Semiconductors

NE1617A

Temperature monitor for microprocessor systems

[1] Any pull-up/pull-down resistor used to connect to GND or V

should be  2k.

8.3 Registers

The device contains more than 9 registers. They are used to store the data of device

set-up and operation results. Depending on the bus communication (either read or write

operations), each register may be called by different names because each register may

have different sub-addresses or commands for read and write operations. For example,

the configuration register is called as WC for write mode and as RC for read mode.

Table 4

shows the names, commands and functions of all registers as well as the register

POR states.

Remark: Attempting to write to a read-command or read from a write-command will

produce an invalid result. The reserved registers are used for factory test purposes and

should not be written.

n.c. n.c. 0101 010

n.c. V

0101 011

GND 1001 100

n.c. 1001 101

1001 110

Table 3. Device slave address

…continued

n.c. = not connected

ADD0

[1]

ADD1

[1]

Address byte

Table 4. Register assignments

RIT 00h 0000 0000 read internal or local temp byte

RET 01h 0000 0000 read external or remote temp byte

RS 02h n/a read status byte

RC 03h 0000 0000 read configuration byte

RCR 04h 0000 0010 read conversion rate byte

RIHL 05h 0111 1111 read internal temp high limit byte

RILL 06h 1100 1001 read internal temp low limit byte

REHL 07h 0111 1111 read external temp high limit byte

RELL 08h 1100 1001 read external temp low limit byte

WC 09h n/a write configuration byte

WCR 0Ah n/a write conversion rate byte

WIHL 0Bh n/a write internal temp high limit byte

WILL 0Ch n/a write internal temp low limit byte

WEHL 0Dh n/a write external temp high limit byte

WELL 0Eh n/a write external temp low limit byte

OSHT 0Fh n/a one-shot command

- 10h n/a reserved

- 11h n/a reserved

- 12h n/a reserved

- 13h n/a reserved

Product data sheet Rev. 5 — 20 March 2012 8 of 30

NXP Semiconductors

NE1617A

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 A 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.

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.

Table 5. Configuration register bit assignments

Bit Symbol POR state Function

7 (MSB) MASK 0 Mask ALERT

interrupt. Interrupt is enabled when this bit

is LOW, and disabled when this bit is HIGH.

6 RUN/STOP 0 Standby or run mode control. When LOW, running mode

is enabled; when HIGH, standby mode is initiated.

5 to 0 - n/a reserved

Product data sheet Rev. 5 — 20 March 2012 9 of 30

NXP Semiconductors

NE1617A

Temperature monitor for microprocessor systems

8.3.4 Conversion rate register

The conversion rate register is used to store programmable conversion data, which

defines the time interval between conversions in standard free-running auto-convert

mode. Table 7

shows all applicable data and rates for the device. Only three LSB bits of

the register are used and other bits are reserved for future use. This register can be

written to and read back over the SMBus using commands of the registers named WCR

and RCR, respectively. The POR default conversion data is 02h (0.25 Hz).

Notice that the average supply current, as well as the device power consumption, is

increased with the conversion rate.

8.3.5 Temperature limit registers

The device has four registers to be used for storing programmable temperature limits,

including the high limit and the low limit for each channel of the external and internal

diodes. Data of the temperature register (RIT and RET) for each channel are compared

with the contents of the temperature limit registers of the same channel, resulting in alarm

conditions. If measured temperature either equals or exceeds the corresponding

temperature limits, an Alert interrupt is asserted and the corresponding flag bit in the

status register is set. The temperature limit registers can be written to and read back using

Table 6. Temperature data format (2’s complement)

Temperature (C) Digital output (8 bits)

+127 0111 1111

+126 0111 1110

+100 0110 0100

+50 0011 0010

+25 0001 1001

+1 0000 0001

0 0000 0000

1 1111 1111

25 1110 0111

50 1100 1110

65 1011 1111

Table 7. Conversion rate control byte

Data Conversion rate (Hz) Average supply current (A typical at V

=3.3V)

00h 0.0625 67

01h 0.125 68

02h 0.25 70

03h 0.5 75

04h 1 80

05h 2 95

06h 4 125

07h 8 180

08h to FFh (reserved) n/a

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P18 P19-P21 P22-P24 P25-P27 P28-P30

NE1617ADS,112

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NXP Semiconductors

Description:

Board Mount Temperature Sensors I2C LOC +/- 2OC AND

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NE1617ADS,112

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