37.4.3.2 Receiver wakeup operationReceiver wakeup and receiver address matching is a hardware mechanism that allows anLPUART receiver to ignore the characters in a message intended for a different receiver.During receiver wakeup, all receivers evaluate the first character(s) of each message, andas soon as they determine the message is intended for a different receiver, they writelogic 1 to the receiver wake up control bit (LPUART_CTRL[RWU]). When RWU bitand LPUART_S2[RWUID] bit are set, the status flags associated with the receiver, withthe exception of the idle bit, IDLE, are inhibited from setting, thus eliminating thesoftware overhead for handling the unimportant message characters. At the end of amessage, or at the beginning of the next message, all receivers automatically forceLPUART_CTRL[RWU] to 0 so all receivers wake up in time to look at the firstcharacter(s) of the next message.During receiver address matching, the address matching is performed in hardware and theLPUART receiver will ignore all characters that do not meet the address matchrequirements.Table 37-2. Receiver Wakeup OptionsRWU MA1 | MA2 MATCFG WAKE:RWUID Receiver Wakeup0 0 X X Normal operation1 0 00 00 Receiver wakeup onidle line, IDLE flag notset1 0 00 01 Receiver wakeup onidle line, IDLE flag set1 0 00 10 Receiver wakeup onaddress mark1 1 11 X0 Receiver wakeup ondata match0 1 00 X0 Address mark addressmatch, IDLE flag not setfor discardedcharacters0 1 00 X1 Address mark addressmatch, IDLE flag set fordiscarded characters0 1 01 X0 Idle line address match0 1 10 X0 Address match on andaddress match off,IDLE flag not set fordiscarded characters0 1 10 X1 Address match on andaddress match off,IDLE flag set fordiscarded charactersFunctional descriptionKL27 Sub-Family Reference Manual , Rev. 5, 01/2016670 Freescale Semiconductor, Inc.
