Forum Discussion

KeeganJ's avatar
KeeganJ
Icon for New Contributor rankNew Contributor
4 years ago

Cyclone 10 GX Transceiver Reset Controller "LockedToData" Signal

I'm instantiating the reset controller IP in order to safely use the the Cyclone 10 GX transceivers, as described in the user manual. My question is why does the reset controller require "rx_is_loc...
Deshi_Intel's avatar
Deshi_Intel
Icon for Regular Contributor rankRegular Contributor
4 years ago

Hi,


rx_is_lockedtodata is status signal that's meant to be used in CDR lockedtodata mode


Since you are using lockedtoref mode, then you can safely ignore rx_is_lockedtodata from transceiver channel operation perspective


However, the tricky question is how to deal with "rx_is_lockedtodata" signal connection to reset controller IP and whether reset operation will be gated by "rx_is_lockedtodata" signal or not. I believe this is your concern.


Sorry I don't have good answer for you. Perhaps you can try and error to see which work out the best for you


Option 1 - Let rx_is_lockedtodata signal connection to reset controller IP float and don't connect to anything

  • Hopefully it won't gate transceiver channel Rx analog reset or RX digital reset
  • If transceiver channel reset is somehow gated by rx_is_lockedtodata then maybe you can explore option 2


Option 2

  • disconnect rx_is_lockedtodata connection between NativePHY and reset controller IP
  • Then create custom state machine design
    • if locktoref = 1, drive rx_is_lockedtodata = 1 to reset controller IP
    • else if locktoref = 0, drive rx_is_lockedtodata = 0 to reset controller IP


Thanks.


Regards,

dlim






KeeganJ's avatar
KeeganJ
Icon for New Contributor rankNew Contributor
4 years ago

Thanks, this is approximately what I was thinking to try also. The reason for using this signal in the reset controller is a bit opaque, but my assumption is that it's just validating the receiver is operational so it can assert rx_ready.

It looks fine in simulation, I will try to validate in hardware over the next few days and report back if there are any issues.