mcf5282 Freescale Semiconductor, Inc, mcf5282 Datasheet - Page 431

• Manufacturer Part Number: mcf5282
• Manufacturer: Freescale Semiconductor, Inc

23.3.6
The receive buffers contain one serial shift register and three receiver holding registers, which act as a
FIFO. URXDn is connected to the serial shift register. The CPU reads from the top of the FIFO while the
receiver shifts and updates from the bottom when the shift register is full (see
the character in the receiver.
Freescale Semiconductor
Field
3–2
1–0
RC
TC
Transmit command field. Selects a single transmit command.
Receive command field. Selects a single receive command.
UART Receive Buffers (URBn)
00
01
10
11
00
01
10
11
NO ACTION TAKEN
TRANSMITTER
ENABLE
TRANSMITTER
DISABLE
NO ACTION TAKEN
RECEIVER ENABLE
RECEIVER DISABLE
Command
Command
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3
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Table 23-7. UCRn Field Descriptions (continued)
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 UART’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.
Causes the receiver to stay in its current mode. If the receiver is enabled, it
remains enabled; if disabled, it remains disabled.
If the UART module is not in multidrop mode (UMR1n[PM] ≠ 11),
enables the UART's receiver and forces it into search-for-start-bit state. If the
receiver is already enabled, this command has no effect.
Disables the receiver immediately. Any character being received is lost. The
command does not affect receiver status bits or other control registers. If the
UART module is programmed for local loopback or multidrop mode, the receiver
operates even though this command is selected. If the receiver is already
disabled, the command has no effect.
Reserved, do not use.
Description
Description
Description
Figure
23-18). RB contains
RECEIVER ENABLE
UART Modules
23-11