SystemC AMS/SystemC synchronization

[htawfik]

Hi

 

I am running the TDF BASK basic example provided in the SystemC AMS User Guide (I ran the modulation only without the demodulation). I am using the variation that make the bit_src module a pure SystemC  module that is to be accessed from SystemC AMS mixer module through a converter port. 

 

My understanding is that the SystemC kernel is blocked by the SystemC AMS kernel. Accessing the converter port from SystemC AMS should trigger the SystemC kernel to advance until time of SystemC kernel = time of SystemC AMS kernel. Please correct me of I am wrong.

 

I have made a small change in the example where I commented the mixer part that reads from the pure SystemC bit_src module. The bit_src is still connected but ports are not accessed. I have added few cout in order to track the execution semantics and I found out the bit_src module is still running each 200 ms (as specified by the example). I don't understand why it does run. Shouldn't it be blocked given that nobody accesses its ports ?

 

I am using SystemC AMS 1.0 and SystemC 2.2.0

 

Thank you for your help

Hanan

[maehne]

It is true that accessing a TDF converter input port will interrupt the execution of the TDF cluster to advance the SystemC time to the point in time at which the DE signal should be sampled using a SystemC wait(time) call. In addition, SystemC-AMS, will perform a wait() at the end of each TDF cluster execution period (i.e., after it has terminated executing the schedule of processing() methods) to synchronize the TDF cluster execution with the progress of the SystemC time. This is necessary to ensure a controlling of the SystemC AMS execution through the standard sc_start() command. Therefore, the SC_THREAD of the DE bit_src will be run each 200 ms, as it is an independent DE process.