Communication Processor Module
16-214
MPC823e REFERENCE MANUAL
MOTOROLA
COMMUNICATION
16
SCCs
For 16x oversampling, the FSB field is decoded as follows:
1111 = Last transmitted stop bit 16/16. Default value after reset.
1110 = Last transmitted stop bit 15/16.
1101 = Last transmitted stop bit 14/16.
1100 = Last transmitted stop bit 13/16.
1011 = Last transmitted stop bit 12/16.
1010 = Last transmitted stop bit 11/16.
1001 = Last transmitted stop bit 10/16.
1000 = Last transmitted stop bit 9/16.
0xxx = Invalid. Do not use.
For 8x oversampling, the FSB field is decoded as follows:
1111 = Last transmitted stop bit 8/8. Default value after reset.
1110 = Last transmitted stop bit 7/8.
1101 = Last transmitted stop bit 6/8.
1100 = Last transmitted stop bit 5/8.
10xx = Invalid. Do not use.
01xx = Invalid. Do not use.
00xx = Invalid. Do not use.
The SCCx UART receiver can always receive fractional stop bits. The next character’s start
bit can begin at any time after the three middle samples of the stop bit have been taken.
16.9.15.14 SCCx UART CONTROLLER ERRORS.
The SCCx UART controller reports
character reception and transmission error conditions via the channel buffer descriptors, the
error counters, and the SCCE–UART register. The modem interface lines can be monitored
by the port B and C pins. The following transmission error can be detected by the SCCx
UART controller.
• CTSx
Lost During Character Transmission
—
When this error occurs, the channel stops
transmission after finishing transmission of the current character from the buffer. The
channel then sets the CT bit in the TX buffer descriptor and generates the TX interrupt
if it is not masked. The channel resumes transmission after the
RESTART TRANSMIT
command is issued and the CTSx
pin is asserted.
Note:
Using the CTSx
signal, the SCCx UART controller also offers an asynchronous
flow control option that does not generate an error. Refer to the FLC bit
description in
Section 16.9.15.15 SCCx UART Mode Register
for information
about flow control.
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