Motorola MC68824 User Manual page 77

II
NIP - NegativelPositive
o
Positive confirmation
1 Negative confirmation
EMP - Empty Transmit Queue
o
If CFD
=
1 and NPV
=
1 in the next FD control word then the TBC sets this queue to not
empty
1 If NPV
=
0 in the next FD control word then the TBC sets this queue to empty
FTL - Frame Too Long
o
No meaning
1 The frame is too long. The actual data length is greater than the frame data length from
the FD which is set by the host. The TBC transmitted the data contained in the first data
buffer or the frame data length set by the host, whichever is the shortest, followed by an
abort sequence.
RES - Reserved
UR - Underrun
o
No underrun occurred
1 Underrun occurred
NR - No Response
o
No meaning
1 If
NIP
=
1 then no response was received to an RWR frame. If
NIP
=
0 then response was
received on one of the following retries.
UF - Unexpected Frame
o
No meaning
1 Unexpected frame received during RWR
RD-RTO - Number of Tries
Number of tries, except if the MAX RETRY LIMIT was reached then it is the number of retries.
Refer to 4.4 REQUEST WITH RESPONSE (RWR) TRANSMISSION and 4.5 RECEPTION OF RWR
FRAMES AND TRANSMISSION OF RESPONSE for further details.
When used in a RECEIVE queue, the frame descriptor confirmationlindication word has the fol-
lowing format and is updated by the TBC:
F E D C
8 A
I
NRV
I
*
I
*
I
*
*Don't Care
NRV - Next Receive Pointer Valid
o
The pointer to the next FD in this receive queue is not valid so this is the last frame in
this receive queue.
The pointer to the next FD in this receive queue is valid.
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MC68824 USER'S MANUAL
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