MPC555CME Freescale Semiconductor, MPC555CME Datasheet - Page 510

• Manufacturer Part Number: MPC555CME
• Description: KIT EVALUATION FOR MPC555
• Manufacturer: Freescale Semiconductor
• Type: Microcontrollerr

Specifications of MPC555CME

• Contents: Module Board, Installation Guide, Power Supply, Cable, Software and more
• Processor To Be Evaluated: MPC555
• Data Bus Width: 32 bit
• Interface Type: RS-232
• For Use With/related Products: MPC555
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

MPC555
USER’S MANUAL
Bit(s)
0:6
10
11
12
7
8
9
/
MPC556
Name
TDRE
RDRF
IDLE
RAF
OR
TC
—
Transmit data register empty. TDRE is set when the byte in TDRx is transferred to the transmit
serial shifter. If this bit is zero, the transfer is yet to occur and a write to TDRx will overwrite the
previous value. New data is not transmitted if TDRx is written without first clearing TDRE.
0 = Transmit data register still contains data to be sent to the transmit serial shifter.
1 = A new character can now be written to the transmit data register.
For transmit queue operation, this bit should be ignored by software.
Transmit complete. TC is set when the transmitter finishes shifting out all data, queued pream-
bles (mark/idle-line), or queued breaks (logic zero).
0 = SCI transmitter is busy.
1 = SCI transmitter is idle.
For transmit queue operation, TC is cleared when SCxSR is read with TC set, followed by a write
to SCTQ[0:15].
Receive data register full. RDRF is set when the contents of the receive serial shifter are trans-
ferred to register RDRx. If one or more errors are detected in the received word, the appropriate
flag(s) (NF, FE, or PF) are set within the same clock cycle.
0 = Receive data register is empty or contains previously read data.
1 = Receive data register contains new data.
For receiver queue operation, this bit should be ignored by software.
Receiver active flag. RAF indicates whether the receiver is busy. This flag is set when the receiv-
er detects a possible start bit and is cleared when the chosen type of idle line is detected. RAF
can be used to reduce collisions in systems with multiple masters.
0 = SCI receiver is idle.
1 = SCI receiver is busy.
Idle line detected. IDLE is set when the receiver detects an idle-line condition (reception of a min-
imum of 10 or 11 consecutive ones as specified by ILT in SCCxR1). This bit is not set by the idle-
line condition when RWU in SCCxR1 is set. Once cleared, IDLE is not set again until after RDRF
is set (after the line is active and becomes idle again). If a break is received, RDRF is set, allow-
ing a subsequent idle line to be detected again.
Under certain conditions, the IDLE flag may be set immediately following the negation of RE in
SCCxR1. System designs should ensure this causes no detrimental effects.
0 = SCI receiver did not detect an idle-line condition.
1 = SCI receiver detected an idle-line condition.
For receiver queue operation, IDLE is cleared when SCxSR is read with IDLE set, followed by a
read of SCRQ[0:15].
Overrun error. OR is set when a new byte is ready to be transferred from the receive serial shifter
to register RDRx, and RDRx is already full (RDRF is still set). Data transfer is inhibited until OR
is cleared. Previous data in RDRx remains valid, but additional data received during an overrun
condition (including the byte that set OR) is lost.
Note that whereas the other receiver status flags (NF, FE, and PF) reflect the status of data al-
ready transferred to RDRx, the OR flag reflects an operational condition that resulted in a loss of
data to RDRx.
0 = RDRF is cleared before new data arrives.
1 = RDRF is not cleared before new data arrives.
Reserved
QUEUED SERIAL MULTI-CHANNEL MODULE
Table 14-25 SCxSR Bit Descriptions
Rev. 15 October 2000
Description
MOTOROLA
14-48