SCLK

SDATA

SCLK

LM3263

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SNVS837 – JUNE 2013

GPO1

GPO1 has two functions. The first function is an input to select the default USID and the second function is to be

a general purpose output.

The state of the GPO1 pin at startup determines the default USID. If the GPO1 pin is low or left floating at

startup, the USID is 0100b. If the GPO1 pin is high at startup, the USID is 0101b. One method to set the GPO1

pin high is to place a pull-up resistor (39K

Ω) on the GPO1 pin.

When the GPO1 pin is used as the general purpose output, GPO_CTRL [6] needs to be set to 1b. Once it has

been enabled as the general purpose output, GPO_CTRL [7] will determine the state driven to the GPO1 pin.

The pull-up resistor needs to be placed either as an external pull-up on the board or through an internal pull-up

on the general purpose input which is tied to the GPO1 pin.

The GPO1 pin can be left floating if unused.

Trigger Registers

Trigger registers are indicated in the RFFE register map by the “Trigger” column. All trigger registers are tied to

each of the TRIG_0-2 register bits. When a trigger register is written directly across the RFFE interface, the new

value will not be loaded into the register until one of the TRIG0-2 register bits is written with a ‘1’ and the

associated TRIG_MSK_x bit for that TRIG_x is not set. (Triggers are ignored when their associated masking bit

is set.) When all 3 TRIG_MSK_0-2 bits are set (all triggers are masked) the trigger feature is disabled and any

trigger registers will be loaded directly at the time of the write operation to that register rather than waiting for a

trigger event to update.

Control Interface Timing Parameters

Figure 26. Clock Timing

Figure 27. Setup and Hold Timing

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