Generate code from polyphase decimator

Hi,

I'm trying to generate code for a sample rate conversion to use on an embedded ARM Cortex M0+ Processor. If I would construct the SRC manually, there would be two interrupt routines: one on the high frequency with calculates one of the sub-filter for the new sample and one on the low frequency wich adds the correct outputs of the sub-filter for the new Sample.

Since I just need downsampling with factor 10, I create a MATLAB dsp.FIRDecimator object. But when I try to use the code-generator it requires in the function an input vector with M (decimation factor) samples. Do I have to calculate the decimation in one function call? This would result in a longer latency and one big calculation block (every M input samples) wich will be very fragmented by interrupts. Is a different implementation available? And is there a decimator implementation with WDF? Since the M0+ is no number cruncher every bit of performance gain is welcome...

Best Regards, Wolfgang Birnbacher