The receiver of the analog SYSREF in RF-DAC tile 0 is designed to capture a rising edge at the input pins and generate a sync pulse that gets distributed internally in a balanced method to all RF-DAC and RF-ADC tiles for the MTS function and the dynamic update event triggering function. The MTS function requires a continuous analog SYSREF clock that generates a continuous sequence of sync pulses during the duration of the MTS procedural call. The Dynamic Update event trigger function, on the other hand, only uses the first detected rising edge after the event is armed (an event update being requested). The arming, which is done using a corresponding API function call, should complete without seeing any sync pulses generated. Otherwise, some blocks will be latched in with the new update value while other blocks do not.
As a result, the sequencing of events and the analog SYSREF waveform must
adhere to the following guidance for the proper operation of each of the two functions.
To simplify the implementation of some clocking designs, an API function call,
XRFdc_MTS_Sysref_Config, is made available to enable and
disable the analog SYSREF receiver, providing a method to gap the SYSREF sync pulses.
Note that this API function is not a timed function, and therefore does not easily sync
across multiple devices. As a result, the API
XRFdc_MTS_Sysref_Config is not meant to be used solely to synchronize the
first rising edge of the SYSREF across multiple devices.