National Semiconductor TPS65132, User Manual

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3.3 V
USB2ANY
I
2
C
Controller EVM
… Pullups?
3.3 V
USB2ANY
I
2
C
Controller EVM
;
Pullups?
2 × 1.5 k
Software Operation
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10 SLVUAO0 – February 2016
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TPS65132L Evaluation Module
6.2 I
2
C Bus Configuration
6.2.1 Slave Address
The EVM software uses the slave address 0x3E to communicate with the TPS65132L device over the I
2
C
bus. This address cannot be changed.
6.2.2 Bus Speed
The I
2
C bus of the EVM can operate in Standard mode (100 kbps) or Fast mode (400 kbps). Select the
desired I
2
C bus speed from the Speed drop-down menu.
6.2.3 Pullups
The USB2ANY interface adapter has pullup resistors for the I
2
C bus. Disable the pullup resistors if they
are not needed.
• Check the Pullups? checkbox if using the I
2
C pullup resistors in the USB2ANY interface adapter (refer
to Figure 11 ). This is the most common setting.
• Uncheck the Pullups? checkbox if there are I
2
C pullup resistors somewhere else in your system (refer
to Figure 12 ).
Figure 11. I
2
C Bus Internal Pullup Connection
Figure 12. I
2
C Bus External Pullup Connection
NOTE: The external pullup resistors (if used) must be connected to 3.3 V ( Figure 12 ). Pullup
voltages lower than 3.3 V can cause incorrect operation. Pullup voltages higher than 3.3 V
can damage the USB2ANY interface adapter.
The maximum value of the external pullup resistors depends on the I
2
C bus capacitance
(refer to UM10204 – I
2
C-bus specification and user manual from NXP). A higher bus
capacitance needs smaller pullup resistors. A value in the range 1.5 k Ω to 10 k Ω works well
in most applications.