MCP4725.py 文件源码

def set_voltage(self, value, persist=False):
        """Set the output voltage to specified value.  Value is a 12-bit number
        (0-4095) that is used to calculate the output voltage from:

          Vout =  (VDD*value)/4096

        I.e. the output voltage is the VDD reference scaled by value/4096.
        If persist is true it will save the voltage value in EEPROM so it
        continues after reset (default is false, no persistence).
        """
        # Clamp value to an unsigned 12-bit value.
        if value > 4095:
            value = 4095
        if value < 0:
            value = 0
        logging.debug('Setting value to {0:04}'.format(value))
        # Generate the register bytes and send them.
        # See datasheet figure 6-2:
        #   https://www.adafruit.com/datasheets/mcp4725.pdf 
        reg_data = [(value >> 4) & 0xFF, (value << 4) & 0xFF]
        if persist:
            self._device.writeList(WRITEDACEEPROM, reg_data)
        else:
            self._device.writeList(WRITEDAC, reg_data)