#!/usr/bin/env python
"""
================================================
ABElectronics Expander Pi 2-Channel ADC, 2-Channel DAC | DAC Speed Demo

run with: python demo_dacspeed.py
================================================

this demo outputs a 4.095V square wave, testing the maximum speed of the DAC
"""

from __future__ import (absolute_import, division, print_function,
                        unicode_literals)

try:
    import ExpanderPi
except ImportError:
    print("Failed to import ADCDACPi from python system path")
    print("Importing from parent folder instead")
    try:
        import sys
        sys.path.append('..')
        import ExpanderPi
    except ImportError:
        raise ImportError(
            "Failed to import library from parent folder")


def main():
    '''
    Main program function
    '''

    # create an instance of the Expander Pi DAC with a gain set to 2
    dac = ExpanderPi.DAC(2)

    while True:
        dac.set_dac_raw(1, 4095)  # set the voltage on channel 1 to 4.095V
        dac.set_dac_raw(1, 0)  # set the voltage on channel 1 to 0V

if __name__ == "__main__":
    main()