Motorola MPC823e - Page 675

Communication Processor Module
MOTOROLA MPC823e REFERENCE MANUAL 16-221
COMMUNICATION
16
PROCESSOR MODULE
SCCs
Figure 16-76. SCC2 UART Receive Buffer Descriptor Example
MRBLR = 8 BYTES FOR SCC2
BUFFER
BYTE 1
BYTE 2
BYTE 8
ETC.
8 BYTES
LONG IDLE PERIOD
FOURTH CHARACTER
HAS FRAMING ERROR!
5 CHARS10 CHARS
CHARACTERS
RECEIVED BY UART
TIME
BUFFER
BYTE 9
BYTE 10
8 BYTES
BUFFER
BYTE 1
BYTE 2
8 BYTES
BYTE 4 HAS
FRAMING ERROR
BUFFER
FULL
BYTE 3
BYTE 4 ERROR!
E
LENGTH
32-BIT BUFFER POINTER
RECEIVE BD 0
STATUS
0008
POINTER
0
E
LENGTH
32-BIT BUFFER POINTER
RECEIVE BD 1
STATUS
0002
POINTER
0
1
ID
0
ID
E
LENGTH
32-BIT BUFFER POINTER
RECEIVE BD 2
STATUS
0004
POINTER
0
ID
0
FR
1
E
LENGTH
32-BIT BUFFER POINTER
RECEIVE BD 3
STATUS
XXXX
POINTER
1
BUFFER
BYTE 5
8 BYTES
RECEPTION
STILL IN
PROGRESS
WITH THIS
BUFFER
PRESENT
TIME
IDLE TIMEOUT
OCCURRED
EMPTY
EMPTY
ADDITIONAL
BYTES WILL BE
STORED UNLESS IDLE
COUNT EXPIRES
(MAX_IDL)