Altera RapidIO MegaCore Function - Manual (Page 39)

Chapter 3: Parameter Settings 3–3
Physical Layer Settings
August 2014 Altera Corporation RapidIO MegaCore Function
User Guide
Baud Rate
Baud rate defines the baud rate based on the value that you specify. Table 1–7 and
Table 1–8 show the baud rates supported by the RapidIO IP core for each device
family. A device family may include devices at speed grades that do not support all
the indicated baud rates.
Table 1–7 and Table 1–8 provide information about the speed
grades supported for each device family, RapidIO mode, and baud rate combination.
Reference Clock Frequency
Reference clock frequency defines the frequency of the reference clock for your
RapidIO IP core internal transceiver. The RapidIO parameter editor allows you to
select any frequency supported by the transceiver.
For more information about the reference clock in high-speed transceiver blocks, and
the supported frequencies, refer to
“Clocking and Reset Structure” on page 4–3 .
Receive Buffer Size
Receive buffer size defines the receive buffer size in KBytes based on the value that
you specify. You can select a receive buffer size of 4, 8, 16, or 32 KBytes.
This parameter is not available for variations that target an Arria 10 device. RapidIO
IP core Arria 10 variations have a Physical layer receive buffer size of 32 KBytes.
Transmit Buffer Size
Transmit buffer size defines the transmit buffer size in KBytes based on the value that
you specify. You can select a transmit buffer size of 4, 8, 16, or 32 KBytes.
This parameter is not available for variations that target an Arria 10 device. RapidIO
IP core Arria 10 variations have a Physical layer transmit buffer size of 32 KBytes.
1 Buffers are implemented in embedded RAM blocks. Depending on the size of the
device used, the maximum buffer size may be limited by the number of available
RAM blocks.
Receive Priority Retry Thresholds
Retry thresholds can be set automatically by turning on Auto-configured from
receiver buffer size
, or manually by specifying the thresholds for Priority 0, Priority
1 , and Priority 2. To specify valid values for these priority thresholds, follow these
four guidelines:
■ Priority 2 Threshold > 9
■ Priority 1 Threshold > Priority 2 Threshold + 4
■ Priority 0 Threshold > Priority 1 Threshold + 4
■ Priority 0 Threshold < (receive buffer size x 1024/64)
Receive priority retry threshold values are numbers of 64-byte buffers. For more
information about retry thresholds, refer to
“Physical Layer Receive Buffer” on
page 4–14 .