TCN75AVOA View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

TCN75AVOA

2-Wire Serial Temperature Sensor

Microchip Technology 

5.3 Registers

The TCN75A has four registers that are user-accessi-

ble. These registers are specified as the Ambient

Temperature (TA) register, the Temperature Limit-set

(TSET) register, the Temperature Hysteresis (THYST)

register and device Configuration (CONFIG) register.

The Ambient Temperature register is a read-only

register and is used to access the ambient temperature

data. The data from the ADC is loaded in parallel in the

register. The Temperature Limit-set and Temperature

Hysteresis registers are read/write registers that

provide user-programmable temperature limits. If the

ambient temperature drifts beyond the programmed

limits, the TCN75A outputs an alert signal using the

ALERT pin (refer to Section 5.3.4.3 “ALERT Output

Configuration”). The device Configuration register

provides access for the user to configure the TCN75A’s

various features. These registers are described in

further detail in the following sections.

The registers are accessed by sending register

pointers to the TCN75A using the serial interface. This

is an 8-bit pointer. However, the two Least Significant

bits (LSbs) are used as pointers and all other bits need

to be cleared <0>. This device has additional registers

that are reserved for test and calibration. If these

registers are accessed, the device may not perform

according to the specification. The pointer description

is shown below.

TCN75A

Resolution

One-Shot

Shutdown

Fault Queue

Alert Polarity

Alert Comp/Int

Configuration

Register

Temperature

Register

THYST

Register

TSET

Register

ALERT Output

Control Logic

ALERT

Output

FIGURE 4-2:

Register Block Diagram.

REGISTER 5-1: REGISTER POINTER

U-0

0

bit 7

U-0

U-0

U-0

U-0

0

0

0

0

U-0

R/W-0

R/W-0

0

P1

P0

bit 0

Legend:

R = Readable bit

-n = Value at POR

W = Writable bit

‘1’ = Bit is set

U = Unimplemented bit, read as ‘0’

‘0’ = Bit is cleared

x = Bit is unknown

bit 7-3

bit 2-0

.

Unimplemented: Read as ‘0’

Pointer bits

00 = Temperature register (TA)

01 = Configuration register (CONFIG)

10 = Temperature Hysteresis register (THYST)

11 = Temperature Limit-set register (TSET)

© 2006 Microchip Technology Inc.

DS21935C-page 11

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