Loop Operation; System Level Interrupt Sources - NXP Semiconductors freescale KV4 Series Reference Manual

Table of Contents

Chapter 46 Universal Asynchronous Receiver/Transmitter (UART) / FlexSCI

Enable single wire operation by setting C1[LOOPS] and the receiver source field,

C1[RSRC]. Setting C1[LOOPS] disables the path from the unsynchronized receiver input

signal to the receiver. Setting C1[RSRC] connects the receiver input to the output of the

TXD pin driver. Both the transmitter and receiver must be enabled (C2[TE] = 1 and

C2[RE] = 1).

46.5.6 Loop operation

In loop operation, the transmitter output goes to the receiver input. The unsynchronized

receiver input signal is disconnected from the UART.

Tx pin output

Figure 46-88. Loop operation (C1[LOOPS] = 1, C1[RSRC] = 0)

Enable loop operation by setting C1[LOOPS] and clearing C1[RSRC]. Setting

C1[LOOPS] disables the path from the unsynchronized receiver input signal to the

receiver. Clearing C1[RSRC] connects the transmitter output to the receiver input. Both

the transmitter and receiver must be enabled (C2[TE] = 1 and C2[RE] = 1).

All registers reset to a particular value are indicated in

Memory map and

There are several interrupt signals that are sent from the UART. The following table lists

the interrupt sources generated by the UART. The local enables for the UART interrupt

sources are described in this table. Details regarding the individual operation of each

interrupt are contained under various sub-sections of

Memory map and

RXEDGIF description

also outlines additional details regarding the RXEDGIF

interrupt because of its complexity of operation. Any of the UART interrupt requests

listed in the table can be used to bring the CPU out of Wait mode.

KV4x Reference Manual, Rev. 2, 02/2015

Freescale Semiconductor, Inc.