Serial Communication Modules
MOTOROLA
MPC801 USER’S MANUAL
16-9
16
TXEN—TX Enable
This bit enables the transmitter block. When this bit is low, the transmitter is disabled and
the transmit FIFO is flushed.
0 = Transmitter is disabled and transmit FIFO is flushed.
1 = Transmitter is enabled.
RXCLKCONT—Receiver Clock Control
This bit controls the operating mode of the receiver. When this bit is low, the receiver is in
16
×
mode where it synchronizes to the incoming datastream and samples at the perceived
center of each bit period. When it is high, the receiver is in 1
datastream on each rising edge of the bit clock.
×
mode where it samples the
0 = 16
1 = 1
×
clock mode.
clock mode.
×
PEN—Parity Enable
This bit controls the parity generator in the transmitter and the parity checker in the receiver.
When this bit is high, they are enabled. When it is low, they are disabled.
0 = Parity is disabled.
1 = Parity is enabled.
ODE—Odd Even
This bit controls the sense of the parity generator and checker. When it is high, odd parity is
generated and expected. When it is low, even parity is generated and expected. This bit
does not function if the PEN bit is low.
0 = Even parity.
1 = Odd parity.
SL—Stop Bits
This bit controls the number of stop bits transmitted after a character. When it is high, two
stop bits are sent. When it is low, one stop bit is sent. However, this bit has no effect on the
receiver that expects one or more stop bits.
0 = One stop bit is transmitted.
1 = Two stop bits are transmitted.
CL—Character Length
This bit controls the character length. When it is high, the transmitter and receiver are in 8-bit
mode. When it is low, they are in 7-bit mode. The transmitter ignores D7 and the receiver
sets it to zero.
0 = 7-bit transmit and receive character length.
1 = 8-bit transmit and receive character length.