Datasheet

ManualsBrandsMicrochip ManualsDigitalTemperature sensor MSOP-8

TCN75A

4.3 Registers

The TCN75A has four registers that are user-accessi-

ble. These registers are specified as the Ambient

Temperature (T

) register, the Temperature Limit-set

SET

) register, the Temperature Hysteresis (T

HYST

)

The Ambient Temperature register is a read-only

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

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 4.3.4.3 “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.

FIGURE 4-2: Register Block Diagram.

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.

ALERT Output

Control Logic

ALERT

Output

Resolution

Temperature

HYST

SET

Configuration

One-Shot

Shutdown

Fault Queue

Alert Polarity

Alert Comp/Int

U-0 U-0 U-0 U-0 U-0 U-0 R/W-0 R/W-0

0 0 0 0 0 0 P1 P0

bit 7 bit 0

bit 7-3 Unimplemented: Read as ‘0’

bit 2-0 Pointer bits

00 = Temperature register

01 = Configuration register

10 = Temperature Hysteresis register

11 = Temperature Limit-set register

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

- n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown