Motorola MCF5282, MCF5281 user manual UCR n Field Descriptions, Bits Value Command Description

Register Descriptions

			Table 23-6. UCRn Field Descriptions
Bits	Value	Command		Description
6–4				MISC Field (This field selects a single command.)
	000	NO COMMAND		—
	001	RESET MODE		Causes the mode register pointer to point to UMR1n.
		REGISTER POINTER
	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–		Clears the delta break bit, UISRn[DB].
		CHANGE INTERRUPT
	110	START BREAK		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.
	111	STOP BREAK		Causes UTXD to go high (mark) within two bit times. Any characters in the transmit 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		Enables operation of the channel’s transmitter. USRn[TxEMP,TxRDY] are set. If the
		ENABLE		transmitter is already enabled, this command has no effect.
	10	TRANSMITTER		Terminates transmitter operation and clears USRn[TxEMP,TxRDY]. If a character is being
		DISABLE		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.

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