Freescale Semiconductor MCF52230 ColdFire, Reference Manual

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UART Modules
26-10 Freescale Semiconductor
MCF52235 ColdFire® Integrated Microcontroller Reference Manual, Rev. 6
Table 26-7 describes UCR n fields and commands. Examples in Section 26.4.2, “Transmitter and Receiver
Operating Modes ,” show how these commands are used.
IPSBAR
Offset:
0x00_0208 (UCR0)
0x00_0248 (UCR1)
0x00_0288 (UCR2) Access: User write-only
7 6 5 4 3 2 1 0
R
W 0 MISC TC RC
Reset: 0 0 0 0 0 0 0 0
Figure 26-7. UART Command Registers (UCRn)
Table 26-7. UCRn Field Descriptions
Field Description
7 Reserved, must be cleared.
6–4
MISC
MISC Field (this field selects a single command)
Command Description
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
Immediately 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 UTXDn low. If the transmitter is empty, break may be delayed up to one bit
time. If the transmitter is active, break starts when character transmission
completes. 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.
Transmitter must be enabled for the command to be accepted. This command
ignores the state of UCTSn.
111
STOP BREAK
Causes UTXDn to go high (mark) within two bit times. Any characters in the
transmit buffer are sent.
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:MCF52234CVM60,
MCF52235CVM60