ADT7484/ADT7486
Preliminary Technical Data
Rev. PrA | Page 10 of 16
Command Code Details
ADT7484/ADT7486 Device Identifier Block
The GetDIB() command retrieves the device identifier block
(DIB), which provides information to identify the capabilities of
the ADT7484/ADT7486. The data returned can be in 8- or 16-
byte format. The full 16 bytes of DIB is detailed in Table 8. 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 8. 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 8. DIB Byte Details
Name
Value
Description
Device Capabilities
0xc0
Fixed address device.
Version/Revision
0x10
Meets Version 1 of the SST
specification
Vendor ID
00x11d4
Contains company ID
number in little endian
format
Device ID
0x7484
or
0x7486
Contains device ID number
in little endian format
Device Interface
0x01
SST device
Function Interface
0x00
Reserved
0x00
Reserved
0x00
Reserved
Vendor Specific ID
0x00
Reserved
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 ADT7484/ADT7486 show a valid
nonzero FCS in response to the Ping() command when
correctly addressed.
Table 9. Ping() Command
Target Address
Write Length
Read Length
FCS
Device Address
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 ADT7484/ADT7486.
Table 10. ResetDevice() Command
Target Address
Write
Length
Read
Length
Reset
command
FCS
Device Address
0x01
0x00
0xf6
GetIntTemp()
The ADT7484/ADT7486 show the local temperature of the
device in response to the GetIntTemp() command. The data has
a little endian, 16-bit, twos compliment format.
GetExtTemp()
Prompted by the GetExtTemp() command, the
ADT7484/ADT7486 show the temperature of the remote diode
in little endian, 16-bit, twos compliment format. The
ADT7484/ADT7486 show 0x8000 in response to this command
if the external diode is an open or short circuit.
GetAllTemps()
The ADT7484 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
ADT7486 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 ADT7484/ADT7486 will
use to correct errors in the external diode. The offset is set in
little endian, 16-bit, twos compliment format. The maximum
offset is ±128°C with +0.25°C resolution.
GetExtOffset()
This command causes the ADT7484/ADT7486 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.
ADT7484/ADT7486 Response to Unsupported Commands
A full list of command codes supported by the ADT7484/
ADT7486 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 ADT7484/ADT7486. The
ADT7484/ADT7486 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.