Datasheet

UART Modules
12-26 MCF5206e USER’S MANUAL MOTOROLA
Start Break
The start break command forces TxD low. If the transmitter is empty, the start of the break
conditions can be delayed by as much as two bit times. If the transmitter is active, the
break begins when transmission of the character is complete. If a character is in the
transmitter shift register, the start of the break is delayed until the character is transmitted.
If the transmitter holding register has a character, that character is transmitted before the
break. The transmitter must be enabled for this command to be accepted. The state of the
CTS input is ignored for this command.
Stop Break
The stop break command causes TxD to go high (mark) within two bit times. Characters
stored in the transmitter buffer, if any, are transmitted.
TC1–TC0 — Transmitter Commands
These bits select a single command as listed in Table 12-9.
The definitions of the transmitter command options are as follows:
No Action Taken
The ‘‘no action taken’’ command causes the transmitter to stay in its current mode. If the
transmitter is enabled, it remains enabled; if disabled, it remains disabled.
Transmitter Enable
The ‘‘transmitter enable’’ command enables operation of the channel's transmitter. The
TxEMP and TxRDY bits in the USR are also set. If the transmitter is already enabled, this
command has no effect.
Transmitter Disable
The ‘‘transmitter disable’’ command terminates transmitter operation and clears the
TxEMP and TxRDY bits in the USR. However, if a character is being transmitted when the
transmitter is disabled, the transmission of the character is completed before the
transmitter becomes inactive. If the transmitter is already disabled, this command has no
effect.
Table 12-9. TCx Control Bits
TC1 TC0 COMMAND
0 0 No Action Taken
0 1 Transmitter Enable
1 0 Transmitter Disable
1 1 Do Not Use
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