Temperature Data Format (Continued)

Temperature

Binary

Hex

- 40 ˚C

11 1011 0000

2B0h

-255.5 ˚C

10 0000 0001

201h

-256 ˚C

10 0000 0000

200h

2.9.4 Temperature Control (Addr: 001 010; 0Ah)

This register is set to the reset value by a Device Reset.

Reg

Add

Register

Name

R/

W

P

O

R

Val

Bit

15

MSb

Bit

14

Bit

13

Bit

12

Bit

11

Bit

10

Bit

9

Bit

8

Bit

7

Bit

6

Bit

5

Bit

4

Bit

3

Bit

2

Bit

1

Bit

0

LSb

001 010

Temperature

Control

R/

W

0h

Reserved

EN2 EN1 EN0 ATE

000000000000

Bit

Type

Description

0

R/W

ATE (Attention Enable). When set, this bit enables an Attention Request signal to be generated by the

LM40, if the EN0, EN1 or EN2 bits of this register are set.

0: Attention Request disabled (from enabled Temperature Sensor- default)

1: Attention Request enabled (from enabled Temperature Sensor)

1

R/W

EN0 (Enable Sensor 0). When this bit is set, the Local Temperature Sensor is enabled for temperature

measurements.

0: Temperature Sensor disabled (default)

1: Temperature Sensor enabled

2

R/W

EN1 (Enable Sensor 1). When this bit is set, the Remote Thermal Diode 1 Temperature Sensor is enabled

for temperature measurements.

0: Temperature Sensor disabled (default)

1: Temperature Sensor enabled

3

R/W

EN2 (Enable Sensor 2). When this bit is set, the Remote Thermal Diode 2 Temperature Sensor is enabled

for temperature measurements.

0: Temperature Sensor disabled (default)

1: Temperature Sensor enabled

15-4

RO

Reserved. Will always read "0".

2.10 VOLTAGE-ONLY MEASUREMENT FUNCTION (TYPE 0010)

This section defines the register structure and operation of the Voltage-Only Measurement Function. The FuncDescriptor value

of this function is ‘0010’.

2.10.1 Operation

The Voltage-Only measurement function is capable of measuring the voltage of voltage measurement points ("sensors"). These

may be general or dedicated inputs (e.g., for backup battery measurement or the supply voltage to the device). The measurement

of all the enabled voltage sensors is cyclic and continuous.

Sensor Scan

The control register of the function defines which voltage sensors (inputs) are included in the scan. A sensor is

scanned only if it is enable by the Sensor Enable bit (EN0, EN1, EN2, EN3 and EN4). The sensors are scanned in an ascending,

round-robin order, based on the sensor number. Disabled sensors are skipped and the next enabled sensor in ascending order

is scanned.

The minimum scan rate is recommended to be 4Hz (i.e., the measurement data is updated at least once in 250 ms), see Section

2.11 for further details. In Low-Power Mode, the scan rate is four times lower than the scan rate in Active Mode. The scan rate

effects the bus bandwidth required to read the results. The sampling rate of the voltage measurements can also be controlled via

the Conversion Rate register, see Section 2.11 for further details.

Data Readout

When a new result is stored in the readout register a Function Event is generated. Reading the Readout register

clears the Status Function 2 flag (SF2) for the Voltage-Only Measurement Function in the Device Status register. The result is

available in the Readout register waiting for the master to read it during the master sensor read sequence. The device should

delay or buffer additional conversions to allow the master time to read the result (see Sensor Scan Rate Section 2.11). If a new

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