
UART Modules
Freescale Semiconductor
31-11
31.3.6
UART Receive Buffers (URBn)
The receive buffers contain one serial shift register and three receiver holding registers, which act as a
FIFO. U
n
RXD 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
). RB contains
the character in the receiver.
3–2
TC
Transmit command field. Selects a single transmit command.
1–0
RC
Receive command field. Selects a single receive command.
Table 31-7. UCRn Field Descriptions (continued)
Field
Description
Command
Description
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
ENABLE
Enables operation of the UART’s transmitter. USRn[TXEMP,TXRDY] are set. If the
transmitter is already enabled, this command has no effect.
10
TRANSMITTER
DISABLE
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.
11
—
Reserved, do not use.
Command
Description
00
NO
ACTION
TAKEN
Causes the receiver to stay in its current mode. If the receiver is enabled, it
remains enabled; if disabled, it remains disabled.
01
RECEIVER
ENABLE
If the UART module is not in multidrop mode (UMR1n[PM]
≠
11),
RECEIVER
ENABLE
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.
10
RECEIVER
DISABLE
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.
11
—
Reserved, do not use.
MCF5329 Reference Manual, Rev 3
Summary of Contents for MCF5329
Page 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...