The SERCOM transmitter output can be used as input source. The transmitter output is TxD for USART, MOSI for SPI, and SDA for I2C. SERCOM input is selected by writing the Input y Source Selection bit group in the LUT Control x register (LUTCTRLx.INSELy) to 0x9. LUTx can be connected to SERCOMx, as indicated in the following table. Before selecting the SERCOM as input source, the SERCOM must be configured.
| LUT | IN[x] | SERCOM |
|---|---|---|
| LUT0 | x = 0,1,2 | SERCOM0 |
| LUT1 | x = 0,1,2 | SERCOM1 |
| LUT2 | x = 0,1,2 | SERCOM2 |
| LUT3 | x = 0,1,2 | SERCOM3 |