16-10
MCF5272 User’s Manual
Register Descriptions
Table 16-6. UCRn Field Descriptions
Bits
Value
Command
Description
7
ENAB
—
Enable autobaud
0 Autobaud disabled.
1 Autobaud enabled. The transmission rate is calculated from the first received
character. If the rate must be recalculated, ENAB must first be cleared and
reset. UISRn[ABC] indicates a transmission rate has been calculated and
loaded into the UART divider registers. UDUn and UDULn must be initialized
to 0x00 before enabling autobaud.
6–4
MISC Field (This field selects a single command.)
000
NO
COMMAND
—
001
RESET
MODE
REGISTER
POINTER
Causes the mode register pointer to point to UMR1n.
010
RESET
RECEIVER
Immediately disables the receiver, clears USRn[FFULL,RxRDY], and reinitializes
the receiver FIFO pointer. No other registers are altered. Because it places the
receiver in a known state, use this command instead of
RECEIVER
DISABLE
when
reconfiguring the receiver.
011
RESET
TRANSMITTER
Disables the transmitter and clears USRn[TxEMP,TxRDY]. No other registers are
altered. Because it places the transmitter in a known state, use this command
instead of
TRANSMITTER
DISABLE
when reconfiguring the transmitter.
100
RESET
ERROR
STATUS
Clears USRn[RB,FE,PE,OE]. Also used in block mode to clear all error bits after
a data block is received.
101
RESET
BREAK
–
CHANGE
INTERRUPT
Clears the delta break bit, UISRn[DB].
110
START
BREAK
Forces TxD low. If the transmitter is empty, the break may be delayed up to one
bit time. If the transmitter is active, the break starts when character transmission
completes. The break is delayed until any character in the transmitter shift
register is sent. Any character in the transmitter holding register is sent after the
break. The transmitter must be enabled for the command to be accepted. This
command ignores the state of CTS.
111
STOP
BREAK
Causes TxD to go high (mark) within two bit times. Any characters in the
transmitter buffer are sent.
3–2
TC Field (This field selects a single command)
00
NO
ACTION
TAKEN
Causes the transmitter to stay in its current mode: if the transmitter is enabled, it
remains enabled; if the transmitter is disabled, it remains disabled.
01
TRANSMITTER
ENABLE
Enables operation of the channel’s transmitter. USRn[TxEMP,TxRDY] are set. If
the transmitter is already enabled, this command has no effect.
10
TRANSMITTER
DISABLE
Terminates transmitter operation and clears USRn[TxEMP,TxRDY]. If a character
is being sent when the transmitter is disabled, transmission completes before the
transmitter becomes inactive. If the transmitter is already disabled, the command
has no effect.
11
—
Reserved, do not use.
Summary of Contents for DigitalDNA ColdFire MCF5272
Page 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Page 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Page 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Page 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Page 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Page 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Page 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Page 338: ...13 44 MCF5272 User s Manual Application Examples ...
Page 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Page 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Page 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Page 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...