Hi Ken, The intended sequence for synchronizing NCO updates is to disable/pause SYSREF, set each desired tile’s mixer event source to a SYSREF event, configure the mixer (type, mode, scale, frequency, etc), and then enable SYSREF. There are two ways to pause/disable SYSREF from triggering events. The first is to assert the `adcX_sysref_gate` pin on the RFDC’s real-time status port interface for each tile intending to be active to SYSREF. This method is only supported in Gen 3 RFSoCs. There have been recent updates in CASPER’s RFDC mask to enable the ADCs real-time interface. To expose that you will need to activate the checkbox “Enable ADC Real-time Ports” under the “System Clocking And Real-time Ports” tab. Once that is enabled, a `adcX_rts_in` port is enabled where X is the tile index 0-3 for the corresponding enabled tiles. The LSB of that interface is `adcX_sysref_gate`. This pin can be driven by a software register in casper, or some other external synchronous event arriving in the fabric, such as a PPS.
The second method for pausing SYSREF is to program the PLL chip producing the SYSREF to change from a continuous SYSREF mode to a pulsed SYSREF mode. In this mode, SYSREF pulses are sent when events need to be triggered. This method requires custom code, out side of what is readily available in CASPER, to program and manipulate the PLLs configuration. The methods for setting the mixer’s event source, and changing all other configurations, are intended to be done from casperfpga. This handles the remote calls to casper’s katcp library. The casperfpga methods are: `set_mixer_event_source()` `set_mixer_mode()` `set_mixer_type()` `set_mixer_fine_ferquency()` Start with first setting the mixer event source to a SYSREF event (`EVNT_SRC_SYSREF`), then use the other methods to configure the rest of the mixer. All of the current configuration settings for the mixer is queried using the `get_mixer_settings()` method. Hope his helps, Mitch > On Aug 16, 2025, at 6:19 PM, Ken Semanov <[email protected]> wrote: > > I am currently calling an NCO update for the purposes of multi-tile synch. > To do this, I use a function called rfdc_update_nco_cmd( ) , linked below. > This method causes the tcpborphserver to update a single NCO located in a > specific tile and a specific NCO. It will then set a trigger update event > for the mixer. > > Unfortunately, I am calling this function remotely over ethernet via the > casper katcp library. This entails a pause between each NCO update session, > as the network traffic is routed, during which earlier NCOs will have > triggered already. The rising edge of a SYSREF clock very likely already > occurred, and successive calls will arrive too late. > > Is it possible to get a more compact version of this method, that would set > all 16 NCOs all at once in a tight loop performed locally? > > Alternatively, should I pause the SYSREF clock and then enable it again? > > My tcpborphserver3 is v8.1 posted to /zcu216update/ > > rfdc_update_nco_cmd() is located in the rfdc branch of > > gitlab ras byu edu > /alpaca/casper/katcp/-/blob/rfsoc/rfdc/tcpborphserver3/rfsoc.c > > Thanks! > > -- > You received this message because you are subscribed to the Google Groups > "[email protected]" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[email protected]>. > To view this discussion visit > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/84228ea0-e2a2-4455-9c0d-754e4f4ba0b8n%40lists.berkeley.edu > > <https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/84228ea0-e2a2-4455-9c0d-754e4f4ba0b8n%40lists.berkeley.edu?utm_medium=email&utm_source=footer>. -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/723EC0ED-0BF0-49B9-8952-991720B336B4%40gmail.com.
