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ASC7511D8

LOW-VOLTAGE 2-WIRE DIGITAL TEMPERATURE SENSOR WITH THERMAL ALARM

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aSC7511

Configuration Register

The configuration register is a read-write register that

stores the controls for masking the ALERT signal, RUN /

STOP control, extended temperature range select and the

pin 6 function select for ALERT or THERM2 . It is located at

address 03h for read and 09h for writing.

Power on default is for all bits reset: no ALERT mask, RUN,

pin 6 is ALERT and normal range, 0°C to 127°C. Table 5

lists the bits of the configuration register.

The mask bit is only functional when pin 6 is configured as

the ALERT pin. When selecting extended range, note that

the values reported will be offset by 64°C and any limits will

have to be adjusted accordingly to match this offset-binary

coding. It is recommended that this configuration not be

changed again, once selected, to avoid confusion.

16

32

64

Reserved

0.0625

0.03125

0.015625

Reserved

08h

09h

0Ah

0Bh to FFh

Table 6. Conversion Rate Register Bit

Assignments

The conversion rate register may be written-to at address

04h. The value stored may be read back at any time from

address 0Ah. The lower four bits define the rate from

0.0625 to 64 conversions per second. The default rate is 16

conversions per second designated by a code of 08h. The

rates are described in Table 6.

A single measurement is controlled separately by the one-

shot register, 0Fh, that is described below.

Bit

Name

Function

0, 1 Reserved

2 Range Select

3, 4 Reserved

0 = 0°C to +127°C

1 = -55°C to +150°C

0 = pin 6 is ALERT

5 ALERT / THERM2

1 = pin 6 is THERM2

6 RUN / STOP

0 = RUN

1 = STOP

7 MASK

0 = ALERT Enabled

1 = ALERT Masked

Table 5. Configuration Register Bit Assignments

ALERT Limit Registers

There are four limit registers for the ALERT function using

six register locations:

• ALERT Remote High Limit (high and low bytes)

• ALERT Remote Low Limit (high and low bytes)

• ALERT Local High Limit

• ALERT Local Low Limit

These registers may be written or read-back at any time at

the addresses in shown in Table 2. Each limit has a default

value at power-up of 85°C for the high limit and 0°C for the

low limit. The ALERT high limits have a dual purpose in that

they may be used to control the alternate function of pin 6,

the ALERT / THERM2 output when that mode is selected.

Conversion Rate Register

The sensor conversion rate register sets the rate of

conversions. Both local and remote sensors are measured

during a measurement cycle.

Note that the values in the alarm registers must match the

data format selected by bit 2, the normal / extended range

selector in the configuration register. The user should

choose either normal or extended range on power-up and

not change this setting otherwise all limits will be invalid

and have to be adjusted accordingly.

Conversions per

Second

Seconds per

Conversion

0.0625

0.125

0.25

0.5

1

2

4

8

16

8

4

2

1

0.5

0.25

0.125

© Andigilog, Inc. 2006

Code

Operation of these registers in thermal management

applications is described in the Operation Section.

00h

01h

One-Shot Register

02h

While the aSC7511 is in standby mode with configuration

03h

register bit 6 high, a single measurement cycle may be

initiated by a write to the one-shot register at address 0Fh.

04h

Any data written is ignored. After the conversion is

05h

completed a set of readings is written to the temperature

06h

registers, comparisons made and alerts generated. The

aSC7511 will then return to standby mode, awaiting the

07h

-8-

www.andigilog.com

August 2006 - 70A04010

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