MC68000 MOTOROLA [Motorola, Inc], MC68000 Datasheet - Page 196

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

Communications Processor (CP)
4-76
POINTER
POINTER
POINTER
POINTER
LEGEND:
STATUS
LENGTH
STATUS
LENGTH
STATUS
LENGTH
LENGTH
STATUS
RECEIVED IN HDLC
A = ADDRESS BYTE
C = CONTROL BYTE
F = FLAG
TWO FRAMES
TIME
F
E
0
E
1
E
E
A
0
0
A
C
32-BIT BUFFER POINTER
32-BIT BUFFER POINTER
32-BIT BUFFER POINTER
32-BIT BUFFER POINTER
STORED IN RX BUFFER
CR = CRC BYTE
I
(24-BITS USED)
I = INFORMATION BYTE
RECEIVE BD 0
(24-BITS USED)
1
(24-BITS USED)
1
(24-BITS USED)
L
RECEIVE BD 2
RECEIVE BD 1
RECEIVE BD 3
L
0
I
XXXX
0008
0003
Figure 4-27. HDLC Receive BD Example
000B
ID
1
F
0
1
F
I
I
I
AB
1
MC68302 USER’S MANUAL
I CR CR F
AFTER CONTROL
ABORT WAS
CLOSED WHEN
CLOSING FLAG
RECEIVED
RECEIVED
BYTE!
BUFFER
BUFFER
BUFFER
EMPTY
FULL
STILL
LINE IDLE
MRBLR = 8 BYTES FOR THIS SCC
STORED IN RX BUFFER
F
LAST I-FIELD BYTE
CONTROL BYTE
CONTROL BYTE
(I-FIELD) BYTES
INFORMATION
A
CRC BYTE 2
ADDRESS 2
CRC BYTE 1
UNEXPECTED ABORT
ADDRESS 1
ADDRESS 1
ADDRESS 2
BUFFER
BUFFER
BUFFER
OCCURS BEFORE
BUFFER
EMPTY
EMPTY
EMPTY
CLOSING FLAG!
A
5
C
ABORT/IDLE
MOTOROLA
8 BYTES
8 BYTES
8 BYTES
8 BYTES
PRESENT
TIME