Altera Stratix GX Transceiver - Manual (Page 61)

Altera Corporation 3–15
January 2005 Stratix GX Transceiver User Guide
Basic Mode
Figure 3–13. Receiver Byte Deserialzer Data Recovery in Logic Array
Receiver Phase Compensation FIFO Buffer
The receiver phase compensation FIFO buffer is located at the FPGA logic
array interface in the receiver block and is four words deep. The buffer
compensates for the phase difference between the clock in the FPGA and
the operating clocks in the transceiver block.
In basic mode, the write port is clocked by the recovered clock from the
CRU. This clock is half the original rate if the byte deserializer is used. The
read clock is clocked by RX_CORECLK.
You can select RX_CORECLK as an optional receiver input port, and it can
also accept a clock supply. The clock that feeds the RX_CORECLK must be
derived from the RX_CLKOUT of its associated receiver channel. The
receiver phase compensation FIFO buffer can only account for phase
differences.
Gigabit Transceiver Block Logic Array
D Q
D Q
rx_out[19..10]
rx_out[9..0]
Byte Boundary
Selection Logic
rx_out_post[9..0]
rx_out_post[19..10]
{rx_out[9..0], rx_out_post[19..10]}
rx_out_post[19..0]
rx_out_align[19..0]
Phase
Compensation
FIFO
Buffer
10
10
10
10
20
10
10