pynq.iop.pmod_led8 — Python productivity for Zynq (Pynq) v1.0

# Source code for pynq.iop.pmod_led8

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    __author__      = "Graham Schelle, Giuseppe Natale, Yun Rock Qu"
    __copyright__   = "Copyright 2016, Xilinx"
    __email__       = "pynq_support@xilinx.com"

    from pynq.iop import iop_const
    from pynq.iop import DevMode
    from pynq.iop import PMODA
    from pynq.iop import PMODB

    class Pmod_LED8(object):
        """This class controls a single LED on the LED8 Pmod.

        The Pmod LED8 (PB 200-163) has eight high-brightness LEDs. Each LED can be
        individually illuminated from a logic high signal.

        Attributes
        ----------
        iop : _IOP
            I/O processor instance used by LED8.
        index : int
            Index of the pin on LED8, from 0 to 7.

        """

        def __init__(self, if_id, index):
            """Return a new instance of a LED object.

            Parameters
            ----------
            if_id : int
                The interface ID (1, 2) corresponding to (PMODA, PMODB).
            index: int
                The index of the pin in a Pmod, from 0 to 7.

            """
            if not if_id in [PMODA, PMODB]:
                raise ValueError("No such IOP for Pmod device.")
            if not index in range(8):
                raise ValueError("Valid pin indexes are 0 - 7.")

            self.iop = DevMode(if_id, iop_const.PMOD_SWCFG_DIOALL)
            self.index = index

            self.iop.start()
            self.iop.write_cmd(iop_const.PMOD_DIO_BASEADDR + \
                                iop_const.PMOD_DIO_TRI_OFFSET, \
                                iop_const.PMOD_CFG_DIO_ALLOUTPUT)

            self.iop.load_switch_config()

        def toggle(self):
            """Flip the bit of a single LED.

            Note
            ----
            The LED will be turned off if it is on. Similarly, it will be turned
            on if it is off.

            Parameters
            ----------
            None

            Returns
            -------
            None

            """
            curr_val = self.iop.read_cmd(iop_const.PMOD_DIO_BASEADDR + \
                                            iop_const.PMOD_DIO_DATA_OFFSET)
            new_val  = (curr_val) ^ (0x1 << self.index)
            self._set_leds_values(new_val)

        def on(self):
            """Turn on a single LED.

            Parameters
            ----------
            None

            Returns
            -------
            None

            """
            curr_val = self.iop.read_cmd(iop_const.PMOD_DIO_BASEADDR + \
                                            iop_const.PMOD_DIO_DATA_OFFSET)
            new_val  = (curr_val) | (0x1 << self.index)
            self._set_leds_values(new_val)

        def off(self):
            """Turn off a single LED.

            Parameters
            ----------
            None

            Returns
            -------
            None

            """
            curr_val = self.iop.read_cmd(iop_const.PMOD_DIO_BASEADDR + \
                                            iop_const.PMOD_DIO_DATA_OFFSET)
            new_val  = (curr_val) & (0xff ^ (0x1 << self.index))
            self._set_leds_values(new_val)

        def write(self, value):
            """Set the LED state according to the input value

            Note
            ----
            This method does not take into account the current LED state.

            Parameters
            ----------
            value : int
                Turn on the LED if value is 1; turn it off if value is 0.

            Returns
            -------
            None

            """
            if not value in (0,1):
                raise ValueError("LED8 can only write 0 or 1.")
            if value:
                self.on()
            else:
                self.off()

        def read(self):
            """Retrieve the LED state.

            Parameters
            ----------
            None

            Returns
            -------
            int
                The data (0 or 1) read out from the selected pin.

            """
            curr_val = self.iop.read_cmd(iop_const.PMOD_DIO_BASEADDR + \
                                            iop_const.PMOD_DIO_DATA_OFFSET)
            return (curr_val >> self.index) & 0x1

        def _set_leds_values(self, value):
            """Set the state for all the LEDs.

            Note
            ----
            Should not be used directly. User should rely on toggle(), on(),
            off(), write(), and read() instead.

            Parameters
            ----------
            value : int
                The state of all the LEDs encoded in one single value

            Returns
            -------
            None

            """
            self.iop.write_cmd(iop_const.PMOD_DIO_BASEADDR + \
                                iop_const.PMOD_DIO_DATA_OFFSET, value)