User`s guide

DWMBB Adapter
The DWMBB has two programmable timeout limits: a normal timeout
limit that ranges from 0 to 15 ms and a short timeout limit that ranges
from 0 to 960 s. The normal timeout limit of 14 to 15 ms is the default
value at power-up and node reset. The short timeout limit is set by
software. The value is used for both response and retry timeouts, as well
as transaction timeouts while waiting for an XMI grant.
Response Timeout—Occurs when the read responses for a DMA read
transaction (READ or IREAD) have not been received within the timeout
period after the transaction has been issued on the XMI. The timed-out
transaction fails, and an interrupt is issued, if enabled.
Retry Timeout—The DWMBB retries an XMI transaction that receives
a NO ACK confirmation. If the transaction does not successfully complete
within the timeout period, the transaction fails, and an interrupt is issued,
if enabled.
When Disable XMI Timeout (Bus Error Register bit <2>) is set, the
DWMBB ignores the timeout value and retries the XMI transaction until
it successfully completes or the DWMBB is reset.
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