Learning How To Use Trends

I am beginning to write an application that will use either PtTrend or PtMtrend to plot data in real time. The graph needs to be constantly updated with new data and must be able to refresh onscreen multiple times a second.

Is it best to use PtTrend or PtMTrend to do this?

Up to this point I have a PtTrend that uses the Got Focus callback to call this code:

PtSetResource(widget, Pt_ARG_TREND_DATA, count, 1);

However, this does not allow me to update in realtime since the graqph will not refresh until I give a return(Pt_CONTINUE);

Does anyone have some suggestions or even example code for PtTrend or PtMtrend that will help me get started?