I am working on a little project with intel galileo gen 2 which involves successive analog voltage readings of a sinusoidal waveform. I am using analogRead() function in Arduino IDE for that purpose. But the on-board ADC is extremely slow.The sampling rate I am getting is terribly small which is 500 samples per second. The clock frequency of the processor is 400MHz, so expected rate is around 1 million samples per second but I am getting nowhere near it. Is there any way to achieve that rate,like by changing the ADC's clock frequency? Arduino uno R3 shield is compatible with the board. Will that help?