Abstract: The QuiPAD is an audio real time FIR filter controlled by a touchpad that shows how powerful is the NXP LPC1768 microcontroller and how it can process signals without the need of a DSP. The project fully utilizes the GPDMA, ADC, DAC, AHB RAM and a TIMER. The flow of the data is as follows: First the DMA takes the data from the ADC to the RAM. Then a FIR filter function takes the data, processes it, and stores it in another section of the RAM. Finally, another DMA takes the processed data from the RAM to the DAC. This is done continuously and by blocks of data. This way the software can take full advantage of the processor pipeline. And the best part, depending on where you press the touchpad, you can change dynamically the cutoff frequency of the filter being used!
Authors: Gonzalo Brusco