Uart Receive Buffers (Urbn) - Freescale Semiconductor MCF52277 Reference Manual

Field
3–2 TC Field (This field selects a single command)
TC
Command
00
NO ACTION TAKEN
01
TRANSMITTER
ENABLE
10
TRANSMITTER
DISABLE
11
1–0 RC (This field selects a single command)
RC
Command
00
NO ACTION TAKEN
01
RECEIVER ENABLE
10
RECEIVER DISABLE
11
30.3.6

UART Receive Buffers (URBn)

The receive buffers (shown in
registers, which act as a FIFO. UnRXD 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
Figure 30-18). RB contains the character in the receiver.
Freescale Semiconductor
Table 30-7. 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.
Figure 30-8) contain one serial shift register and three receiver holding
MCF52277 Reference Manual, Rev. 1
Description
Description
Description
UART Modules
RECEIVER ENABLE
30-11