Simulink and TI Launchpad F28377s Serial and Receive Synchronization

Hi everyone, I wanna do a boost converter simulation by using the TI Launchpad F28377s and Simulink. First, I create the boost converter model in simulink by using the simcape/Power system/Specialized technology library components. Also I add the serial receive and send block to cominicate with the launchpad. In this model, boost converter output voltage is sended to the launchpad F28377s, and gate signal is generate by using the received duty cycle from the launcpad. After, I write the required PI controller code in CCS v6.1, it inculude the seral receive interrupt rutine.In my code, PI controller calculate the duty cycle, and this duty cycle sended the to the simulink enviroment in serial receive interurrupt rutine. Using the this duty cycle, gate signal is generated and applied tot the boost converter.

But, I think, I have Synchronization problem.I want to stop the simulink enviroment until the launchpad send the data to simulink. After now I want to stop launchpad and wait the data from the simulink. Is this possiable or not. and how can I do this.