IPSERIALLITE Altera, IPSERIALLITE Datasheet - Page 74

• Manufacturer Part Number: IPSERIALLITE
• Manufacturer: Altera

Specifications of IPSERIALLITE

• Lead Free Status / RoHS Status: Not Compliant

SerialLite Link Configuration
3–42
SerialLite MegaCore Function User Guide
Table 3–27
Flow Control
The SerialLite MegaCore function provides flow control as an optional
means of exerting back-pressure on a data source when data
consumption is too slow. Use it to ensure that the receive FIFO buffers do
not overflow.
1
If flow control is not enabled and a receive FIFO buffer overflows, a link
error is declared, and the link is restarted. Link errors are described in the
section
The flow control feature in the SerialLite MegaCore function works by
having the receiving end of the link issue a PAUSE instruction to the
transmitting end of the link when a receive FIFO buffer threshold is
breached. The instruction causes the transmitter to cease transmission for
a specified pause duration. Once the pause has expired, transmission
resumes.
If the receive FIFO buffer is still in breach of the threshold when the pause
is about to expire, the receiver automatically renews the pause in time to
ensure that no data leaks out between pauses.
Minimum
Table 3–27. Retry-on-Error Timeout Margin Values
0
MegaCore Function Version 1.1.0
“Error Handling” on page
The flow control is not needed to handle the situation where two
different clock sources are used on the transmitting and
receiving sides of the links; clock compensation handles that
without the need for flow control. Flow control is only needed
when the system logic on the receiving end of the link is reading
the data more slowly than the system logic on the transmitting
end of the link is sending data.
shows the margin values for the retry-on-error timeout.
Maximum
2
16
-n*
Default
5
3–54.
The number of system clock cycles
beyond the required minimum that the
retry-on-error circuitry waits before
automatically resending data. Available
only if the retry-on-error feature has been
enabled.
* n represents the required minimum
timeout.
Description
Altera Corporation
August 2005