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Altera_Forum's avatar
Altera_Forum
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15 years ago

Stratix II GX serdes synchro problem

Hi,

I'm a newbie here.

I have some difficulties to have the ALT2GXB serdes to synchronised.

I use the basic 10bit mode (single width), without the 8b/10b encoder.

Manual bit sliping mode doesn't seems to operate properly, I use the K28.5 symbol as the sync pattern. I toggle the bit_slip signal till the rx_patterndetect is active and them stop toggling bit_slip (i don't pay attention if bit_slip is high or low).

the transmitted pattern is for testing always the k28.5 symbol (17C)h. rx_patterndetect stay high for just one clock period, even if the bit_slip is no more toggled, i expect rx_patterndetect to remain high till the K28.5 symbol is present as the world aligner as aligned to the sync pattern, Am I correct?

Is there something I missed here?

Can I use the automatic alignment state machine is the 8b/10b encoder is not use? reading through the altera doc, i'm not sure that could work in my system as i'm transmitting 10-bit PRBS symbols, so the K28.5 could appear in the transmission and forcing the state-machine to realign...

Any help would be great.

thanks.

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    You should read the Handbook section on this: http://www.altera.com/literature/hb/stx2gx/stxiigx_sii5v2_01.pdf, specifically 2-80 and 2-81. The rx_bitslip signal is active on the rising edge only, one rising edge one bit slipped. Pg. 1-6 of this document goes over the supported modes of the Word Aligner. It seems with a 10-bit pattern you could use Manual Alignment, using rx_enapatternalign, rx_syncstatus and rx_patterndetect.