I am currently trying to implement a polyphase decimation filter by using core generator in ISE 7.1
The filter has been both implemented by using DA FIR and MAC. The DA FIR filter is working as it supposes to be, but MAC doesn't. I can't really see why.
All the inputs and control signals feeding into these filters are the same. They are running in exactly the same environment. The only difference between these two filters that I know is that the output of DA FIR is 28 bits and the output of MAC is 29 bits.
My question is does the MAC filter requires special care compare with DA FIR.
Please help me. Any information will be appreciated.