TC77

DS20092A-page 10

 2002 Microchip Technology Inc.

FIGURE 3-2:

Temperature Read Timing Diagram - (Reading only the first 13 Bits of the

Temperature Register).

FIGURE 3-3:

Temperature Read Followed By A Write To The Configuration Register Timing.

Diagram.

It is recommended that the user write all ‘0’s or all ‘1’s

to the Configuration register. While the following codes

can be transmitted to the TC77, any other code may

put the TC77 into a test mode reserved by Microchip for

calibration and production verification tests.

•00 hex

•01 hex

•03 hex

•07 hex

• 0F hex

• 1F hex

• 3F hex

• 7F hex

• FF hex

The following communication steps can be used to

obtain the Manufacturer's ID and put the device into the

Continuous Conversion mode. The Manufacturer’s ID

register is only accessible for a read operation, if the

TC77 is in Shutdown mode.

1.

CS goes low to initiate the communication cycle.

2.

Read 16 bits of temperature data from the

Temperature register.

3.

Write 16 bits of data (i.e. XXFF hex) to the Con-

figuration register to enter Shutdown mode.

4.

Read the 16 bits from the Manufacturer's ID reg-

ister (C15:C8 = 54 hex) to verify that the sensor

is a Microchip device.

5.

Write 8 to 16 bits of data (00 or 0000 hex) to

enter Continuous Conversion Mode.

6.

Return CS high to terminate the communication

cycle.

The time between a complete temperature conversion

and data transmission is approximately 300 msec.

CS

CLK

SI/O

HI-Z

HI-Z

TT

T

12

11

10

T

9

T

7

T

6

T

5

T

4

T

3

T

2

T

1

T

0

18

13

T

8

CS

CLK

SI/O

HI-Z

18

8

8

8

1

HI-Z

11

HI-Z

TEMPERATURE REGISTER

Notes:

1.

Bit 2 = 0 during power-up for the first

temperature conversion.

2.

Bit 2 =1 after the completion of the first tem-

perature conversion following power-up or a

reset event.

3.

Bits 1 and 0 are “DON”T CARES”.

CONFIGURATION REGISTER

Notes:

1.

XX00 = Continuous Conversion Mode

2.

XXFF = Shutdown Mode

T

12

T

11

T

10

T

9

T

8

T

7

T

6

T

5

T

4

T

3

T

2

T

1

T

0

BIT

2

C

15

C

14

C

13

C

12

C

11

C

10

C

9

C

8

C

7

C

6

C

5

C

4

C

3

C

2

C

1

C

0