MC68000 MOTOROLA [Motorola, Inc], MC68000 Datasheet - Page 433

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

E.1.1.4.1 Receive BD Control/Status Word. To initialize the buffer, the user should write
bits 15-12 and clear bits 11-10 and 5-0. The IMP clears bit 15 when the buffer is closed and
sets bits 5-0 depending on which error occurred.
E—Empty
X—External Buffer
W—Wrap (final BD in table)
I—Interrupt (The RXF bit in the event register is set when a complete frame is received,
independent of the I bit.)
L—Last in Frame
F—First in Frame
Bits 9–6—Reserved for future use
LG—Rx Frame Length Violation
NO—Rx Nonoctet Aligned Frame
AB—Rx Abort Sequence
MOTOROLA
0 = This data buffer is full or has been closed due to an error condition.
1 = This data buffer is empty; must be set by the user to enable reception into this buff-
0 = The data buffer associated with this BD is in internal dual-port RAM.
1 = The data buffer associated with this BD is in external memory.
0 = This is not the last BD in the receive BD table.
1 = This is the last BD in the receive BD table.
0 = The RXB bit in the event register is not set when this buffer is closed.
1 = The RXB bit (or RXF bit, if this is the last buffer in a frame) in the event register is
0 = This buffer is not the last buffer in a frame.
1 = This buffer is the last buffer in a frame.
0 = This buffer is not the first buffer in a frame.
1 = This buffer is the first buffer in a frame.
0 = No frame length violation occurred.
1 = A frame length violation was detected. Up to the number of bytes specified in the
0 = An octet aligned frame was received.
1 = A nonoctet aligned frame was received.
0 = No abort was received.
1 = A minimum of seven ones was received during frame reception.
er.
set when this buffer is closed.
maximum frame length will be written to the buffer (or buffers, if multiple buffers per
frame).
MC68360 USER’S MANUAL
SCC Programming Reference
E-11