Datasheet

9 SERDESUB-21USB User’s Guide SNLU101 – April 2012
JP8,VR1: Address Decoder
Reference Description Setting Connector
JP8
DS90UB903Q
I
2
C Device ID Address
Selection
Default address: 0xB0’h
Enabled –
With jumper
VSS –
Default address
(Default)
JP8 &
VR1
R
ID value adjustment
(via screw)
JP8 MUST
have a jumper to
use VR1 potentiometer.
VR1 = 0Ω to 100KΩ
Clockwise
Decreases
RID value
Counter-
Clockwise
Increases
RID value
The ID[x] (CAD) pin is used to set the physical slave address of the DS90UB903Q (I
2
C
only) to allow up to six devices on the bus using only a single pin. The Address Decoder
employs a 10 k pull up resistor to +1.8V and a variable potentiometer (VR1) for the pull
down resistor R
ID
to GND to generate six unique values based on the table below. Once
the address bits are latched on power up, the device will keep the slave address until a
power down or reset condition occurs.
Figure 3. ID[x] Pin Connection Diagram