MC68000 MOTOROLA [Motorola, Inc], MC68000 Datasheet - Page 179

• Manufacturer Part Number: MC68000
• Manufacturer: MOTOROLA [Motorola, Inc]

MOTOROLA
POINTER
POINTER
POINTER
POINTER
STATUS
LENGTH
LENGTH
LENGTH
LENGTH
STATUS
STATUS
STATUS
RECEIVED BY UART
CHARACTERS
TIME
E
0
E
1
0
E
0
E
32-BIT BUFFER POINTER
32-BIT BUFFER POINTER
32-BIT BUFFER POINTER
32-BIT BUFFER POINTER
10 CHARS
(24-BITS USED)
RECEIVE BD 1
RECEIVE BD 0
RECEIVE BD 3
(24-BITS USED)
(24-BITS USED)
(24-BITS USED)
RECEIVE BD 2
0008
0004
0002
XXXX
ID
ID
1
0
ID
0
Figure 4-21. UART Rx BD Example
MC68302 USER’S MANUAL
FR
1
LONG IDLE PERIOD
FRAMING ERROR
BYTE 4 HAS
IDLE TIMEOUT
OCCURRED
RECEPTION
PROGRESS
WITH THIS
STILL IN
BUFFER
BUFFER
FULL
MRBLR = 8 BYTES FOR THIS SCC
STORED UNLESS IDLE
Communications Processor (CP)
COUNT EXPIRES
BYTES WILL BE
BYTE 4 ERROR!
HAS FRAMING ERROR!
FOURTH CHARACTER
ADDITIONAL
(MAX_IDL)
BUFFER
BUFFER
BUFFER
BYTE 10
BYTE 9
EMPTY
EMPTY
BUFFER
BYTE 2
BYTE 3
BYTE 5
BYTE 1
BYTE 8
BYTE 1
BYTE 2
ETC.
5 CHARS
PRESENT
TIME
8 BYTES
8 BYTES
8 BYTES
8 BYTES
4-59