EP2SGX90EF1152C3 Altera, EP2SGX90EF1152C3 Datasheet - Page 37

• Manufacturer Part Number: EP2SGX90EF1152C3
• Description: Stratix II GX
• Manufacturer: Altera

Altera Corporation
October 2007
reduce the interface speed. For example, at 6.375 Gbps, the transceiver
logic has a double-byte-wide data path that runs at 318.75 MHz in a ×20
deserializer factor, which is above the maximum FPGA interface speed.
When using the byte deserializer, the FPGA interface width doubles to
40-bits (36-bits when using the 8B/10B encoder) and the interface speed
reduces to 159.375 MHz.
Byte Ordering Block
The byte ordering block shifts the byte order. A pre-programmed byte in
the input data stream is detected and placed in the least significant byte
of the output stream. Subsequent bytes start appearing in the byte
positions following the LSB. The byte ordering block inserts the
programmed PAD characters to shift the byte order pattern to the LSB.
Based on the setting in the MegaWizard
ordering block can be enabled either by the rx_syncstatus signal or by
the rx_enabyteord signal from the PLD. When the rx_syncstatus
signal is used as enable, the byte ordering block reorders the data only for
the first occurrence of the byte order pattern that is received after word
alignment is completed. You must assert rx_digitalreset to perform
byte ordering again. However, when the byte ordering block is controlled
by rx_enabyteord, the byte ordering block can be controlled by the
PLD logic dynamically. When you create your functional mode in the
MegaWizard, you can select byte ordering block only if rate matcher is
not selected.
Receiver Phase Compensation FIFO Buffer
The receiver phase compensation FIFO buffer resides in the transceiver
block at the FPGA boundary and cannot be bypassed. This FIFO buffer
compensates for phase differences and clock tree timing skew between
the receiver clock domain within the transceiver and the receiver FPGA
clock after it has transferred to the FPGA.
Table 2–9. Byte Deserializer Input and Output Widths
Input Data Width (Bits)
20
16
10
8
Stratix II GX Device Handbook, Volume 1
Deserialized Output Data Width to the
®
Plug-In Manager, the byte
Stratix II GX Architecture
FPGA (Bits)
40
32
20
16
2–29