Interrupt Status Word 1 - Motorola MC68824 User Manual

TXRWR - Transmitted Request With Response Frame
This bit is set when the TBC has finished processing a transmitted RWR frame and its response.
This does not necessarily indicate that the frame was successfully transmitted or that an
appropriate response frame was received. Setting this bit indicates that the status word of
the FD of the RWR frame contains the detailed status of the frame.
TXRDF - Transmitted Response Data Frame
This bit is set when the TBC has finished processing a transmitted response data frame after
receiving a RWR data frame. This does not necessarily indicate that the frame was successfully
transmitted. Setting this bit indicates that the status word of the FD of the response frame
contains the detailed status of the frame.
TXDF - Transmitted Data Frame
This bit is set when the TBC has finished processing a transmitted non-RWR frame or non-
response data frame. This does not necessarily indicate that the frame was successfully
transmitted. Setting this bit indicates that the status word of the FD of the frame contains
the detailed status of the frame.
RXRWR - Received Request with Response Frame
This bit is set when the TBC accepts a valid non-retry RWR data frame, see 4.4 REQUEST
WITH RESPONSE (RWR) TRANSMISSION for the definition of retry. This bit is set only after
the confirmation word has been written to the FD, the FD has been linked to the appropriate
receive queue, and the TBC has written a pointer to the FD in the RWR pointer field of the
initialization table. If a RWR frame addressed to the TBC is received with an error (e.g., noise,
FCS error, overrun, lack of BDs), this bit will not be set even if the frame is accepted and
linked to the appropriate receive queue. If such a frame is accepted, the RX data frame bit
will be set although the frame control is that of a RWR frame.
RXDF - Received Data Frame
This bit is set when the TBC accepts a non-RWR data frame or an invalid request with response
frame, after the confirmation word has been written to the FD and the FD has been linked
to the appropriate receive queue.
2.2.11.2 INTERRUPT STATUS WORD 1. The format of interrupt status word 1 is shown below:
Offset F E D C B A 9 8 7 S 5 4 3 2 1 0
AC
I
MODER
I
*
I
LAS
I
TCE
I
BIEX I WAS I NRES I RECl IUNEXF10\ SA \ UEXFS\ NSI \ NS \ SC \ FTX \ DMAD \
*Reserved
DMAD - Duplicate MAC Address Detected
This bit is set when the TBC receives a control frame with SA equal to TS, when it is sure
that this frame is not the echo of the TBC's own transmission. This means that there is another
station in the ring with the same TS address as this station. Upon detecting such an event,
the TBC sets this bit and goes OFFLINE.
FTX - Faulty Transmitter
This bit is set when the value of transmitter fault count stored in the private area exceeds
seven. The value of the transmitter fault count is incremented each time the station sequences
to the end of the token contention process and loses or fails to pass the token to any successor.
Neither of these failures occurs in normal operation. The value of transmitter fault count is
reset to zero if the station either enters the ring or successfully solicits a new successor, since
such an event indicates that another station correctly heard a transmission from this station.
Upon detecting the event of faulty transmitter, the TBC sets this bit and goes OFFLINE.
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