DS110RT410_15 Datasheet, PDF (20/60 Pages) Texas Instruments – Low-Power Multi-Rate Quad Channel Retimer

DS110RT410
SNLS460A – MAY 2013 – REVISED OCTOBER 2015
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7.5 Programming
• SMBus Master Configuration Mode
• SMBus Slave Configuration Mode
The configuration mode is selected by the state of the SMBus Enable pin (pin 20) when the DS110RT410 is
powered-up. This pin should be either left floating or tied to the device V_DD through an optional 1-kΩ resistor. The
effect of each of these settings is listed in Table 4.
PIN
SETTING
Float
High (1)
Table 4. SMBus Enable Settings
CONFIGURATION MODE
DESCRIPTION
SMBus Master Mode
SMBus Slave Mode
Device reads its configuration from an external
EEPROM on power-up.
Device is configured over the SMBus by an
external controller.
READ_EN PIN
Pull low to initiate reading configuration data
from external EEPROM
Tie low to enable proper address strapping
on power-up
7.5.1 SMBus Strap Observation
Register 0x00, bits 7:4 and register 0x06, bits 3:0
In order to communicate with the DS110RT410 over the SMBus, it is necessary for the SMBus controller to know
the address of the DS110RT410. 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 DS110RT410 to tell what its SMBus address is
unless it is already known.
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 DS110RT410 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 DS110RT410 is set to an SMBus Write address of 0x32.
20
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