Do the following: 

Use the TRG OUT of the evaluation board as a "busy". Only if this signal goes low (meaning that the readout of the board is complete and the board has been restarted), then re-enable triggers in your trigger logic.

/Stefan

> Hi Stefan,
> No we only use one evaluation board. We use the evaluation board as a part of our beam test setup. It includes a telescope based on the current PSI46V2.1 CMS Pixel chip and a trigger logic board for triggering the telescope and the evaluation board. This includes a 
> handshake between every device and the tlu
> e.g. the tlu expects an answer for each trigger.
> If the trigger comes within this first 200 mus it seems that not every trigger is accepted.
> In this moment our readout would 'die' since the tlu is waiting for the handshake.