How exactly does the rx_std_signaldetect work in the Cyclone V

JHubb2 · ‎07-04-2019

So I am developing a high speed networking system using the Cyclone V and more specifically it's XCVR IPs. Everything appears to function apart from one peculiar thing. The rx_std_signaldetect line as I understand it tells you when you have a sender of data, however I can't seem to ever deassert it, when the line is disconnected in external loopback the flag stays high. There isn't an overabundance of information about it online either.

Can anyone explain under what conditions it is deasserted?

CheePin_C_Intel · ‎07-05-2019

Hi, As I understand it, you have some inquiries related to the rx_std_signaldetect output port. Generally this signal will be asserted when the incoming signal meet a certain set of thresholds that you set. Also, please note that the signal detect circuitry requires input data stream to be 8b10b coded. In other words, you would need to enable the 8b10b blocks as well. As a quick start, you may refer to the V-Series Trasnceiver PHY IP Core User Guide -> "Table 16-15: Bit Reversal and Polarity Inversion Parameters" -> "Enable rx_std_signaldetect port" for the QSF assignments required for SATA/SAS application as example and try if it works for you. The following are the example from user guide for your reference: set_instance_assignment -name XCVR_RX_SD_ENABLE ON set_instance_assignment -name XCVR_RX_SD_THRESHOLD 7 set_instance_assignment -name XCVR_RX_COMMON_MODE_VOLTAGE VTT_OP55V set_instance_assignment -name XCVR_RX_SD_OFF 1 set_instance_assignment -name XCVR_RX_SD_ON 2 Please let me know if there is any concern. Thank you. Best regards, Chee Pin

CheePin_C_Intel · ‎07-09-2019

Hi, Just would like to follow up with you on this. Thank you.

JHubb2 · ‎07-10-2019

I haven't yet tried playing around with this signal, I will get back to you in a few days when I do.

CheePin_C_Intel · ‎07-11-2019

Sure, please feel free to keep me posted. Thank you.

CheePin_C_Intel · ‎07-17-2019

Hi, Just would like to follow up with you on this. thank you.

CheePin_C_Intel · ‎07-19-2019

Hi,

As I understand it, it has been some time since I last heard from you. I would set this case to closed at this moment. Feel free to file a new case if you have any further question related to this request. Thank you for your understanding.

Best regards,

Chee Pin