EMC1184-A-AIA Datasheet EMC1184-A-AIA, EMC1184-A-AIA-TR | P16-P18

Quad Channel 1°C Temperature Sensor with Beta Compensation and 1.8V SMBus Communications

Datasheet

Revision 1.0 (07-11-13) 16 SMSC EMC1184

DATASHEET

4.2.1 Write Byte

The Write Byte is used to write one byte of data to the registers, as shown in Table 4.2.

4.2.2 Read Byte

The Read Byte protocol is used to read one byte of data from the registers as shown in Table 4.3.

4.2.3 Send Byte

The Send Byte protocol is used to set the internal address register pointer to the correct address

location. No data is transferred during the Send Byte protocol as shown in Table 4.4.

4.2.4 Receive Byte

The Receive Byte protocol is used to read data from a register when the internal register address

pointer is known to be at the right location (e.g. set via Send Byte). This is used for consecutive reads

of the same register as shown in

Table 4.5.

Table 4.2 Write Byte Protocol

START

SLAVE

ADDRESS WR

ACK

ADDRESS ACK

DATA ACK STOP

1 -> 0 YYYY_YYY 0 0 XXh 0 XXh 0 0 -> 1

Table 4.3 Read Byte Protocol

START SLAVE

ADDRESS

WR ACK REGISTER

ADDRESS

ACK START SLAVE

ADDRESS

RD ACK REGISTER

DATA

NACK STOP

1 -> 0 YYYY_

YYY

0 0 XXh 0 1 -> 0 YYYY_

YYY

10 XX 10 -> 1

Table 4.4 Send Byte Protocol

START

SLAVE

ADDRESS WR

ACK

ADDRESS ACK STOP

1 -> 0 YYYY_YYY 0 0 XXh 0 0 -> 1

Table 4.5 Receive Byte Protocol

START

SLAVE

ADDRESS RD ACK REGISTER DATA NACK STOP

1 -> 0 YYYY_YYY 1 0 XXh 1 0 -> 1

Quad Channel 1°C Temperature Sensor with Beta Compensation and 1.8V SMBus Communications

Datasheet

SMSC EMC1184 17 Revision 1.0 (07-11-13)

DATASHEET

4.3 Alert Response Address

The ALERT output can be used as a processor interrupt or as an SMBus Alert.

When it detects that the ALERT pin is asserted, the host will send the Alert Response Address (ARA)

to the general address of 0001_100xb. All devices with active interrupts will respond with their client

address as shown in

Table 4.6.

The EMC1184 will respond to the ARA in the following way:

1. Send Slave Address and verify that full slave address was sent (i.e. the SMBus communication

from the device was not prematurely stopped due to a bus contention event).

2. Set the MASK_ALL bit to clear the ALERT pin.

APPLICATION NOTE: The ARA does not clear the Status Register and if the MASK_ALL bit is cleared prior to the

Status Register being cleared, the ALERT

pin will be reasserted.

Table 4.6 Alert Response Address Protocol

START

ALERT

RESPONSE

ADDRESS RD

ACK

DEVICE

ADDRESS NACK STOP

1 -> 0 0001_100 1 0 YYYY_YYY 1 0 -> 1

Quad Channel 1°C Temperature Sensor with Beta Compensation and 1.8V SMBus Communications

Datasheet

Revision 1.0 (07-11-13) 18 SMSC EMC1184

DATASHEET

Chapter 5 Product Description

The EMC1184 is an SMBus temperature sensor. The EMC1184 monitors one internal diode and up to

three externally connected temperature diodes.

Thermal management is performed in cooperation with a host device. This consists of the host reading

the temperature data of both the external and internal temperature diodes of the EMC1184 and using

that data to control the speed of one or more fans.

The EMC1184 has two levels of monitoring. The first provides a maskable ALERT / THERM2 signal

to the host when the measured temperatures exceeds user programmable limits. This allows the

EMC1184 to be used as an independent thermal watchdog to warn the host of temperature hot spots

without direct control by the host. The second level of monitoring provides a non-maskable interrupt

on the

THERM pin if the measured temperatures meet or exceed a second programmable limit.

For the EMC1184, External Diode channels 2 and 3 are only compatible with general purpose diodes

(such as a 2N3904).

Figure 5.1 shows a system level block diagram of the EMC1184.

5.1 Modes of Operation

The EMC1184 has two modes of operation.

 Active (Run) - In this mode of operation, the ADC is converting on all temperature channels at the

programmed conversion rate. The temperature data is updated at the end of every conversion and

the limits are checked. In Active mode, writing to the one-shot register will do nothing.

 Standby (Stop) - In this mode of operation, the majority of circuitry is powered down to reduce

supply current. The temperature data is not updated and the limits are not checked. In this mode

of operation, the SMBus is fully active and the part will return requested data. Writing to the one-

shot register will enable the device to update all temperature channels. Once all the channels are

updated, the device will return to the Standby mode.

Figure 5.1 System Diagram for EMC1184

CPU / GPU

EMC1184

Host

DP1

DN1

SMDATA

Thermal

Junction

SMCLK

SMBus

Interface

THERM / ADDR

ALERT / THERM2

Power

Control

VDD

GND

VDD = 3.3V

1.8V – 3.3V

DN2 / DP3

DP2 / DN3

Optional

Anti-parallel

diode

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P18 P19-P21 P22-P24 P25-P27 P28-P30 P31-P33 P34-P36 P37-P39 P40-P42 P43-P45 P46-P48

EMC1184-A-AIA

Mfr. #:

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Manufacturer:

Microchip Technology

Description:

Board Mount Temperature Sensors 1.8V SMBus Dual Tmp Sensor /w Alerts

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EMC1184-A-AIA

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