MOTOROLA
UNIVERSAL ASYNCHRONOUS RECEIVER/TRANSMITTER MODULE
MMC2001
11-10
REFERENCE MANUAL
TRDYEN — Transmitter Ready Interrupt Enable
Setting this bit enables an interrupt when the transmitter has one or more slots avail-
able in the TX FIFO. The fill level in the TX FIFO at which an interrupt is generated is
controlled by the TxFL bits. While this bit is negated, the transmitter interrupt is dis-
abled.
0 =
TX interrupt disabled
1 =
TX interrupt enabled
At reset, this bit is cleared to zero.
TXEN — Transmitter Enable
This bit enables or disables the transmitter. While UARTEN and TXEN bits are set,
and DOZE bit is cleared, the transmitter is enabled. If this bit is cleared in the middle
of a transmission, the UART disables the transmitter immediately and starts marking
ones.
The transmitter FIFO cannot be written to when this bit is cleared.
0 =
Transmitter disabled
1 =
Transmitter enabled
At reset, this bit is cleared to zero.
RxFL — Receiver FIFO Interrupt Trigger Level
These bits control the threshold at which a maskable interrupt will be generated by
the receiver. A maskable interrupt will be generated whenever the data level in the RX
FIFO reaches the selected threshold.
At reset, these bits are cleared to zero.
RRDYEN — Receiver Ready Interrupt Enable
Setting this bit enables an interrupt when the receiver has data in the RX FIFO. The
fill level in the RX FIFO at which an interrupt is generated is controlled by the RxFL
bits. Clearing this bit disables RX interrupts.
0 =
RX interrupt disabled
1 =
RX interrupt enabled
At reset, this bit is cleared to zero.
RXEN — Receiver Enable
Setting this bit enables the receiver. When the receiver is enabled, if the RXD line is
already low, the receiver does not recognize break characters, since it requires a valid
one-to-zero transition before it can accept any character.
0 =
Receiver disabled
1 =
Receiver enabled
At reset, this bit is cleared to zero.
Table 11-3 RxFL Field Settings
Value
Meaning
00
Interrupt if RX FIFO contains one or more character
01
Interrupt if RX FIFO contains four or more characters
10
Interrupt if RX FIFO contains eight or more characters
11
Interrupt if RX FIFO contains fourteen or more characters
Freescale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
nc.
..