Serial Communication Controllers (SCCs)
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MC68360 USER’S MANUAL
CM—Continuous Mode
0 = Normal operation.
1 = The E-bit is not cleared by the CP after this BD is closed, allowing the associated
data buffer to be overwritten automatically when the CP next accesses this BD.
However, the E-bit will be cleared if an error occurs during reception, regardless of
the CM bit.
DE—DPLL Error
This bit is set by the HDLC controller when a DPLL error has occurred during the reception
of this buffer. In decoding modes where a transition is promised every bit, the DE bit will
be set when a missing transition has occurred.
LG—Rx Frame Length Violation
A frame length greater than the maximum defined for this channel was recognized (only
the maximum-allowed number of bytes (MFLR) is written to the data buffer). This event
will not be reported until the Rx BD is closed and the RXF bit is set, after receipt of the
closing flag. The actual number of bytes received between flags is written to the data
length field of this BD.
NO—Rx Nonoctet Aligned Frame
A frame that contained a number of bits not exactly divisible by eight was received.
AB—Rx Abort Sequence
A minimum of seven consecutive ones was received during frame reception.
CR—Rx CRC Error
This frame contains a CRC error. The received CRC bytes are always written to the re-
ceive buffer.
OV—Overrun
A receiver overrun occurred during frame reception.
CD—Carrier Detect Lost
The carrier detect signal was negated during frame reception. This bit is only valid when
working in the NMSI mode.
Data Length
Data length is the number of octets written by the CP into this BD’s data buffer. It is written
by the CP once as the BD is closed.
When this BD is the last BD in the frame (L = 1), the data length contains the total number
of frame octets (including 2 or 4 bytes for CRC).
The actual amount of memory allocated for this buffer should be greater than or equal to
the contents of the MRBLR.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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