Motorola MC68824 User Manual page 91

II
WARNING
The TBC may send a response to a previous RWR frame as a response to a new
RWR frame in the following cases:
• If a second, new RWR frame arrives immediately after a RWR frame whose
response was not ready within two slot times from its arrival (this new frame
is considered to be a retry) .
• If the response from the host is issued to the TBC at the same time as a second
RWR frame arrives, even if a non-RWR frame addressed to this station arrived
previously. In this case, the RESPONSE READY command is executed only after
complete reception of the RWR frame. Thus, the response is considered a valid
response to the second request and will be transmitted. This scenario also can
take place if the response was ready to be transmitted but, due to high load
on the bus, the TBC was not able to execute the RESPONSE READY command
prior to receiving the second RWR frame.
Note that in these cases, the host did not respond in time to the last retry of a RWR frame, while
according to the 802.4 standard, the host should respond in time to the first one. Thus, these
situations should not occur.
MOTOROLA
4-18
MC68824 USER'S MANUAL