10

SMBus Thermal Sensor with External Diode Input

TCM1617

TCM1617-1

2/5/99

 2001 Microchip Technology Inc.

DS21485A

Stop Condition (STOP)

Communications must be terminated by a stop condi-

tion (a Low to High transition of SDA while SCL is High). The

Stop Condition must be communicated by the transmitter to

the TCM1617. (Refer to TCN75 data sheet for serial bus

timing diagrams.)

REGISTER SET AND PROGRAMMER’S

MODEL

TCM1617 Command Set

The TCM1617 supports four SMBus command proto-

cols. These are READ_BYTE, WRITE_BYTE, SEND_BYTE,

and RECEIVE_BYTE. See System Management Bus Speci-

fication Rev. 1.0 for details.

Command Byte Description

Command

Code

Function

RIT

00h

Read Internal Temp (INT_TEMP)

RET

01h

Read External Temp (EXT_TEMP)

RS

02h

Read Status Byte (STATUS)

RC

03h

Read Configuration Byte (CONFIG)

RCR

04h

Read Conversion Rate Byte

(CONV_RATE)

RIHL

05h

Read Internal High Limit

(INT_HLIM)

RILL

06h

Read Internal Low Limit (INT_LLIM)

REHL

07h

Read External High Limit

(EXT_HLIM)

RELL

08h

Read External Low Limit

(EXT_LLIM)

WC

09h

Write Configuration Byte (CONFIG)

WCR

0Ah

Write Conversion Rate Byte

(CONV_RATE)

WIHL

0Bh

Write Internal High Limit

(INT_HLIM)

WILL

0Ch

Write Internal Low Limit (INT_LLIM)

WEHL

0Dh

Write External High Limit

(EXT_HLIM)

WELL

0Eh

Write External Low Limit

(EXT_LLIM)

OSHT

0Fh

One Shot Temp Measurement

RMID

FEh

Read Manufacturer ID (MFR_ID)

RMREV

FFh

Read Manufacturer Revision

Number (MFR_REV)

Configuration Register (Config), 8-Bits,

Read/Write

Configuration Register (Config)

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

Mask1 Chip Stop

Reserved

Bit

POR State Function

Operation

D[7]

0

Interrupt Mask

1 = mask ALERT#,

(see text)

0 = don’t mask

ALERT #

D[6]

0

Standby switch

1 = standby,

0 = normal

D[5] – D[0]

0

Reserved –

N/A

Always returns

zero when read.

A/D Conversion Rate Register

(CONV_RATE), 8-Bits, Read/Write

A/D Conversion Rate Register (CONV_RATE)

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

Reserved

MSB

X

LSB

Bit

POR State Function

Operation

D[7:3]

0

Reserved – Always

N/A

returns zero when

read.

D[2:0]

010b

Conversion rate bits.

See below.

A/D Conversion Rate Selection

D2

D1

D0

Conversion Rate

Sa/sec

0

0

0

0.0625

0

0

1

0.125

0

1

0

0.25

011

0.5

100

1.0

101

2.0

110

4.0

111

8.0

NOTE: Conversion rate denotes actual sampling of both internal

and

external sensors.

NOTE: Proper device operation is NOT guaranteed if undefined locations

(10h to FDh) are addressed. In case of erroneous SMBus operation

(RECEIVE_BYTE command issued immediately after

WRITE_BYTE command) the TCM1617 will ACKnowledge the

address and return 1111 1111b to signify an error. Under no

condition will it implement an SMBus “timeout.”