i am building a arduino based device which is powered by one single 9 volt batterie.
it receives analog and gate signals from synthesizers with its on board analog/digital convertors and digital pins and outputs signals via one mcp4921 dac and on board digital pins.
i want to buffer, protect and maybe scale signals of the dac and adc with LM358 single supply opamps.
i could find plenty of examples for audio modules with +/- supply's
and how to protect microcontroller inputs from negative and to high voltages but nothing for single supply devices.
thanks in advance for any help and hints