mc68hc11f1cpu3 Freescale Semiconductor, Inc, mc68hc11f1cpu3 Datasheet - Page 93

• Manufacturer Part Number: mc68hc11f1cpu3
• Description: Mc68hc11f1 Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

RWU — Receiver Wakeup Control
SBK — Send Break
7.6.4 Serial Communication Status Register
SCSR — SCI Status Register
TDRE — Transmit Data Register Empty Flag
TC — Transmit Complete Flag
RDRF — Receive Data Register Full Flag
IDLE — Idle Line Detected Flag
TECHNICAL DATA
RESET:
At least one character time of break is queued and sent each time SBK is written to
one. As long as the SBK bit is set, break characters are queued and sent. More than
one break may be sent if the transmitter is idle at the time the SBK bit is toggled on
and off, as the baud rate clock edge could occur between writing the one and writing
the zero to SBK.
The SCSR provides inputs to the interrupt logic circuits for generation of the SCI sys-
tem interrupt.
This flag is set when SCDR is empty. Clear the TDRE flag by reading SCSR and then
writing to SCDR.
This flag is set when the transmitter is idle (no data, preamble, or break transmission
in progress). Clear the TC flag by reading SCSR and then writing to SCDR.
This flag is set if a received character is ready to be read from SCDR. Clear the RDRF
flag by reading SCSR and then reading SCDR.
This flag is set if the RxD line is idle. Once cleared, IDLE is not set again until the RxD
line has been active and becomes idle again. The IDLE flag is inhibited when RWU =
1. Clear IDLE by reading SCSR and then reading SCDR.
0 = Normal SCI receiver
1 = Wakeup enabled and receiver interrupts inhibited
0 = Break generator off
1 = Break codes generated
0 = SCDR busy
1 = SCDR empty
0 = Transmitter busy
1 = Transmitter idle
0 = SCDR empty
1 = SCDR full
0 = RxD line is active
1 = RxD line is idle
TDRE
Bit 7
1
TC
6
1
Freescale Semiconductor, Inc.
For More Information On This Product,
SERIAL COMMUNICATIONS INTERFACE
RDRF
5
0
Go to: www.freescale.com
IDLE
4
0
OR
0
3
NF
2
0
FE
1
0
Bit 0
—
0
$102E
7-7