Truth Table Inputs Selection

Input Overview

The inputs can be individually:

OFF
Driven by peripherals
Driven by internal events from the Event System
Driven by I/O pin inputs
Driven by other LUTs

Internal Feedback Inputs (FEEDBACK)

The output from a sequencer can be used as an input source for the two LUTs it is connected to.

Figure 1. Feedback Input Selection

When selected (INSELy=FEEDBACK in LUTnCTRLx), the sequencer (SEQ) output is used as input for the corresponding LUTs.

Linked LUT (LINK)

When selecting the LINK input option, the next LUT’s direct output is used as LUT input. In general, LUT[n+1] is linked to the input of LUT[n]. LUT0 is linked to the input of the last LUT.

Linking all LUTs on a Device with Four LUTs

LUT1 is the input for LUT0
LUT2 is the input for LUT1
LUT3 is the input for LUT2
LUT0 is the input for LUT3 (wrap-around)

Figure 2. Linked LUT Input Selection

Event Input Selection (EVENTx)

Events from the Event System can be used as inputs to the LUTs by writing to the INSELn bit groups in the LUT n Control B and C registers.

I/O Pin Inputs (IO)

When selecting the IO option, the LUT input will be connected to its corresponding I/O pin. Refer to the I/O Multiplexing section in the data sheet for more details about where the LUTn-INy pins are located.

Peripherals

The different peripherals on the three input lines of each LUT are selected by writing to the Input Select (INSEL) bits in the LUT Control (LUTnCTRLB and LUTnCTRLC) registers.