Stratix II GX Transceiver: Does 8b/10b coding work properly?

Hi Faruk,

I'm sorry, but I have not much experience with SFP modules. But my suggestion is to try the "unspecific" mode in combination with the 8b/10b encoding of the fpga. In my case, there is a possibility to configure the SFP-Module via I2C bus. Fortunetely, the default mode is "unspecific" and I don't need to use this.

With using NRZ, I am afraid you will get problems with clock recovery, too. As I know, you need a seperate clock signal for NRZ and everything could become complicated... Is there a special reason for using NRZ?

In between, I solved my problem with 8b/10b coding. I didn't notice that every byte is transferred with the least significant bit first. So, in the MegaWizard, you have to write down the 8b/10b code (20b) of the LSB-first-ordered bytes of the pattern bytes (usually Comma, BC). Additionally, while sending this the tx_ctrlenable has to be "0011", indicating that the two right bytes 0000BC1C are control bytes (K28.5 and K28.0). having those signals set, a single rx_enapatternalign on a rising edge works and the rx_syncstatus gets high (1111). with this signal, it is possible to set tx_ctrlenable to 0000 again.

Daniel