Communication Processor Module
MOTOROLA
MPC823 USER’S MANUAL
16-391
SMC
COMMUNICATION
16
PROCESSOR
MODULE
ID—Buffer Closed on Reception of Idles
This bit indicates that the buffer has closed because a programmable number of consecutive
idle sequences have been received. The communication processor module writes this bit
after the received data is in the associated data buffer.
BR—Buffer Closed on Reception of Break
This bit indicates that the buffer has closed because a break sequence has been received.
The communication processor module writes this bit after the received data is in the
associated data buffer.
0 = No break sequence is received.
1 = Buffer closed upon reception of a break sequence.
FR—Framing Error
This bit indicates that a character with a framing error has been received and located in the
last byte of this buffer. A framing error is a character without a stop bit. A new receive buffer
is used to receive additional data. The communication processor module writes this bit after
the received data is in the associated data buffer.
PR—Parity Error
This bit indicates that a character with a parity error has been received and located in the
last byte of this buffer. A new receive buffer is used to receive additional data. The
communication processor module writes this bit after the received data is in the associated
data buffer.
OV—Overrun
This bit indicates that a receiver overrun has occurred during message reception. The
communication processor module writes this bit after the received data is in the associated
data buffer.
DATA LENGTH
This field represents the number of octets the communication processor module writes into
this buffer descriptor data buffer. After the data is received in the associated data buffer, the
communication processor module writes this field once the buffer descriptor closes.
RX DATA BUFFER POINTER
This field always points to the first location of the associated data buffer and must be even.
The buffer can reside in internal or external memory. The communication processor module
writes this bit after the received data is in the associated data buffer.
Note: The actual amount of memory allocated for this buffer should be greater than or
equal to the MRBLR entry.