SNLS459 – APRIL 2011
Table 5. Control/Shared Registers
Address (Hex)
Bits
Default Value (Hex)
Mode
Description
0x00
7:4
0x0
R
SMBus Address Strap
Observation <3:0>
0x01
7:5
0x6
R
Device Revision
4:0
0x11
R
Device ID
0x04
6
0x0
R/W/SC
Self-Clearing Reset for
Control/Shared Registers
5
0x0
R/W
Reset for SMBus Master
Mode
4
0x0
R/W
Force EEPROM
Configuration
0x05
7
0x0
R/W
Disable Master Mode
EEPROM Configuration
4
(1)
R
EEPROM Read Complete
3
0x0
R
Set on Channel 0 Interrupt
2
0x0
R
Set on Channel 1 Interrupt
1
0x0
R
Set on Channel 2 Interrupt
0
0x0
R
Set on Channel 3 Interrupt
0x06
3:0
0X0
R/W
Diagnostic Test Control
Set to 0xa to read SMBus
strap values from register
0x00
0xff
3
0x0
R/W
Selects All Channels for
Register Write
See
2
0x0
R/W
Enables Register Write to
One or All Channels and
Register Read from One
Channel
See
1:0
0x0
R/W
Selects Target Channel
for Register Reads and
Writes
See
(1)
There is no default value. This bit always indicates whether the EEPROM read is complete or not.
SMBus Strap Observation
Register 0x00, bits 7:4 and register 0x06, bits 3:0
In order to communicate with the DS125RT410 over the SMBus, it is necessary for the SMBus controller to know
the address of the DS125RT410 . The address strap observation bits in control/shared register 0x00 are primarily
useful as a test of SMBus operation. There is no way to get the DS125RT410 to tell you what its SMBus address
is unless you already know what it is.
In order to use the address strap observation bits of control/shared register 0x00, it is necessary first to set the
diagnostic test control bits of control/shared register 0x06. This four-bit field should be written with a value of 0xa.
When this value is written to bits 3:0 of control/shared register 0x06, then the value of the SMBus address straps
can be read in register 0x00, bits 7:4. The value read will be the same as the value present on the
ADDR3:ADDR0 lines when the DS125RT410 was powered up. For example, if a value of 0x1 is read from
control/shared register 0x00, bits 7:4, then at power-up the ADDR0 line was set to 1 and the other address lines,
ADDR3:ADDR1, were all set to 0. The DS125RT410 is set to an SMBus Write address of 0x32.
20
Copyright © 2011, Texas Instruments Incorporated
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