MC9S12T64 Datasheet, PDF (452/608 Pages) Motorola, Inc – Specification

Freescale Semiconductor, Inc.
Serial Communications Interface (SCI)
addressed process the frames that follow. Any receiver for which a
message is not addressed can set its RWU bit and return to the standby
state. The RWU bit remains set and the receiver remains on standby
until another idle character appears on the RX input signal.
Idle line wakeup requires that messages be separated by at least one
idle character and that no message contains idle characters.
The idle character that wakes a receiver does not set the receiver idle
bit, IDLE, or the receive data register full flag, RDRF.
The idle line type bit, ILT, determines whether the receiver begins
counting logic 1s as idle character bits after the start bit or after the stop
bit. ILT is in SCI control register 1 (SCIxCR1).
Address mark
wakeup
(WAKE = 1)
In this wakeup method, a logic 1 in the most significant bit (msb) position
of a frame clears the RWU bit and wakes up the SCI. The logic 1 in the
msb position marks a frame as an address frame that contains
addressing information. All receivers evaluate the addressing
information, and the receivers for which the message is addressed
process the frames that follow. Any receiver for which a message is not
addressed can set its RWU bit and return to the standby state. The RWU
bit remains set and the receiver remains on standby until another
address frame appears on the RX input signal.
The logic 1 msb of an address frame clears the receiver’s RWU bit
before the stop bit is received and sets the RDRF flag.
Address mark wakeup allows messages to contain idle characters but
requires that the msb be reserved for use in address frames.
NOTE: With the WAKE bit clear, setting the RWU bit after the RX input signal
has been idle can cause the receiver to wake up immediately.
Single-Wire
Operation
Normally, the SCI uses two pins for transmitting and receiving. In
single-wire operation, the RxD pin is disconnected from the SCI. The
SCI uses the TxD pin for both receiving and transmitting.
MC9S12T64Revision 1.1.1
Serial Communications Interface (SCI)
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