Visible to Intel only — GUID: nik1409872185749
Ixiasoft
Visible to Intel only — GUID: nik1409872185749
Ixiasoft
1.2.2.1.2. Bit-Slip Mode
Slipping the received data by one bit effectively shifts the word boundary by one bit. You can implement a controller in the FPGA fabric to iteratively control the rx_std_bitslip signal until the word aligner output matches the predefined word alignment pattern to achieve synchronization.
PCS Mode | PMA–PCS Interface Width (bits) | Word Alignment Operation |
---|---|---|
Single Width | 8 |
|
10 | ||
Double Width | 16 | |
20 |
For this example, consider that 8'b11110000 is received back-to-back and 16'b0000111100011110 is the predefined word alignment pattern. A rising edge on the rx_std_bitslip signal at time n + 1 slips a single bit 0 at the MSB position, forcing the rx_parallel_data to 8'b01111000. Another rising edge on the rx_std_bitslip signal at time n + 5 forces rx_parallel_data to 8'b00111100. Another rising edge on the rx_std_bitslip signal at time n + 9 forces rx_parallel_data to 8'b00011110. Another rising edge on the rx_std_bitslip signal at time n + 13 forces the rx_parallel_data to 8'b00001111. At this instance, rx_parallel_data in cycles n + 12 and n + 13 is 8'b00011110 and 8'b00001111, respectively, which matches the specified 16-bit alignment pattern 16'b0000111100011110.