I have attached a signal flow chart of a sonic indicator. A set of four harmonically related tones are generated and mixed within the FPGA. Those tones rise or fall in response to a pulse-width change at the input. This tonal information is output via I2C. A second I2C output contains the magnitude of input change, which is used to control volume. This is a battery powered application, so I would like to use the smallest chip I can get away with. Thanks.
battery powered <-> FPGA does not really fit get a microprocessor or a DSP