ADT7484A/ADT7486A

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8

Command Code Details

ADT7484A/ADT7486A Device Identifier Block

The GetDIB() command retrieves the device identifier

block (DIB), which provides information to identify the

capabilities of the ADP7484A/ADT7486A. The data

returned can be in 8− or 16−byte format. The full 16−bytes

of DIB is detailed in Table 3. The 8-byte format involves the

first eight bytes described in this table. Byte-sized data is

returned in the respective fields as it appears in Table 3.

Word-sized data, including vendor ID, device ID, and data

values use little endian format, that is, the LSB is returned

first, followed by the MSB.

Table 3. DIB Byte Details

Byte

Name

Value

Description

0

Device

Capabilities

0xc0

Fixed address device

1

Version/

Revision

0x10

Meets Version 1 of the

SST specification

2, 3

Vendor ID

00x11d4

Contains company ID

number in little endian

format

4, 5

Device ID

0x7484

or

0x7486

Contains device ID

number in little endian

format

6

Device

Interface

0x01

SST device

7

Function

Interface

0x00

Reserved

8

Reserved

0x00

Reserved

9

Reserved

0x00

Reserved

10

Reserved

0x00

Reserved

11

Reserved

0x00

Reserved

12

Reserved

0x00

Reserved

13

Reserved

0x00

Reserved

14

Revision ID

0x05

Contains revision ID

15

Client Device

Address

0x48 to

0x50

Dependent on the state

of the address pins

Ping()

The Ping() command verifies if a device is responding at

a particular address. The ADT7484A/ADT7486A show a

valid nonzero FCS in response to the Ping() command when

correctly addressed.

Table 4. Ping() Command

Target Address

Write Length

Read Length

FCS

Device Address

0x00

0x00

ResetDevice()

This command resets the register map and conversion

controller. The reset command can be global or directed at

the client address of the ADT7484A/ADT7486A.

Table 5. Reset Device() Command

Target Address

Write

Length

Read

Length

Reset

Command

FCS

Device Address

0x01

0x00

0xf6

GetIntTemp()

The ADT7484A/ADT7486A show the local temperature

of the device in response to the GetIntTemp() command. The

data has a little endian, 16-bit, twos complement format.

GetExtTemp()

Prompted by the GetExtTemp() command, the

ADT7484A/ADT7486A show the temperature of the

remote diode in little endian, 16-bit, twos complement

format. The ADT7484A/ADT7486A show 0x8000 in

response to this command if the external diode is an open or

short circuit.

GetAllTemps()

The ADT7484A shows the local and remote temperatures

in a 4-byte block of data (internal temperature first, followed

by External Temperature 1) in response to a GetAllTemps()

command. The ADT7486A shows the local and remote

temperatures in a 6-byte block of data (internal temperature

first, followed by External Temperature 1 and External

Temperature 2) in response to this command.

SetExtOffset()

This command sets the offset that the ADT7484A/

ADT7486A will use to correct errors in the external diode.

The offset is set in little endian, 16-bit, twos complement

format. The maximum offset is

±128°C with +0.25°C

resolution.

GetExtOffset()

This command causes the ADT7484A/ADT7486A to

show the offset that they are using to correct errors in the

external diode. The offset value is returned in little endian

format, that is, LSB before MSB.

ADT7484A/ADT7486A Response to Unsupported

Commands

A full list of command codes supported by the

ADT7484A/ADT7486A is given in Table 7. The offset

registers (Command Codes 0xe0 and 0xe1) are the only

registers that the user can write to. The other defined

registers are read only. Writing to Register Addresses 0x03

to 0xdf shows a valid FSC, but no action is taken by the

ADT7484A/ADT7486A. The ADT7484A/ADT7486A

show an invalid FSC if the user attempts to write to the

devices between Command Codes 0xe2 to 0xee and no data

is written to the device. These registers are reserved for the

manufacturer’s use only, and no data can be written to the

device via these addresses.