Ucrn Field Descriptions - Motorola ColdFire MCF5281 User Manual

Register Descriptions
Bits Value Command
6–4
000
NO COMMAND
001
RESET MODE
REGISTER POINTER
010
RESET RECEIVER
011
RESET TRANSMITTER
100
RESET ERROR STATUS
101
RESET BREAK
CHANGE INTERRUPT
110
START BREAK
111
STOP BREAK
3–2
00
NO ACTION TAKEN
01
TRANSMITTER
ENABLE
10
TRANSMITTER
DISABLE
11 —
23-10
Table 23-6. UCRn Field Descriptions
MISC Field (This field selects a single command.)
—
Causes the mode register pointer to point to UMR1n.
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.
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
Clears USRn[RB,FE,PE,OE]. Also used in block mode to clear all error bits after a data
block is received.
– Clears the delta break bit, UISRn[DB].
Forces UTXD 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.
Causes UTXD to go high (mark) within two bit times. Any characters in the transmit buffer
are sent.
TC Field (This field selects a single command)
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.
Enables operation of the channel's transmitter. USRn[TxEMP,TxRDY] are set. If the
transmitter is already enabled, this command has no effect.
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.
Reserved, do not use.
MCF5282 User's Manual
Description
RECEIVER DISABLE
when reconfiguring the transmitter.
when reconfiguring the
MOTOROLA