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

# Source code for pynq.iop.pmod_adc

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

    import struct
    from time import sleep
    from pynq import MMIO
    from pynq.iop import request_iop
    from pynq.iop import iop_const
    from pynq.iop import PMODA
    from pynq.iop import PMODB

    PMOD_ADC_PROGRAM = "pmod_adc.bin"
    PMOD_ADC_LOG_START = iop_const.MAILBOX_OFFSET+16
    PMOD_ADC_LOG_END = PMOD_ADC_LOG_START+(1000*4)

    class Pmod_ADC(object):
        """This class controls an Analog to Digital Converter Pmod.

        The Pmod AD2 (PB 200-217) is an analog-to-digital converter powered by
        AD7991. Users may configure up to 4 conversion channels at 12 bits of
        resolution.

        Attributes
        ----------
        iop : _IOP
            I/O processor instance used by the ADC
        mmio : MMIO
            Memory-mapped I/O instance to read and write instructions and data.
        log_running : int
            The state of the log (0: stopped, 1: started).

        """

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

            Parameters
            ----------
            if_id : int
                The interface ID (1, 2) corresponding to (PMODA, PMODB).

            """
            if not if_id in [PMODA, PMODB]:
                raise ValueError("No such IOP for Pmod device.")

            self.iop = request_iop(if_id, PMOD_ADC_PROGRAM)
            self.mmio = self.iop.mmio
            self.log_running = 0

            self.iop.start()

        def reset(self):
            """Reset the Pmod ADC.

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

            Returns
            -------
            None

            """
            self.mmio.write(iop_const.MAILBOX_OFFSET + \
                            iop_const.MAILBOX_PY2IOP_CMD_OFFSET, 0x1)
            while (self.mmio.read(iop_const.MAILBOX_OFFSET +
                                    iop_const.MAILBOX_PY2IOP_CMD_OFFSET) == 0x1):
                sleep(0.001)

        def read_raw(self, ch1=1, ch2=0, ch3=0):
            """Get the raw value from the Pmod ADC.

            When ch1, ch2, and ch3 values are 1 then the corresponding channel
            is included.

            For each channel selected, this method reads and returns one sample.

            Note
            ----
            The 4th channel is not available due to the jumper (JP1) setting on
            ADC.

            Note
            ----
            This method reads the raw value from ADC.

            Parameters
            ----------
            ch1 : int
                1 means include channel 1, 0 means do not include.
            ch2 : int
                1 means include channel 2, 0 means do not include.
            ch3 : int
                1 means include channel 3, 0 means do not include.

            Returns
            -------
            list
                The raw values read from the 3 channels of the Pmod ADC.

            """
            if (ch1 not in range(2)):
                raise ValueError("Valid value for ch1 is 0 or 1.")
            if (ch2 not in range(2)):
                raise ValueError("Valid value for ch2 is 0 or 1.")
            if (ch3 not in range(2)):
                raise ValueError("Valid value for ch3 is 0 or 1.")
            cmd= (ch3 << 6) | (ch2 << 5) | (ch1 << 4) | 3

            # Send the command
            self.mmio.write(iop_const.MAILBOX_OFFSET +
                            iop_const.MAILBOX_PY2IOP_CMD_OFFSET, cmd)

            # Wait for I/O processor to complete
            while not (self.mmio.read(iop_const.MAILBOX_OFFSET +
                                  iop_const.MAILBOX_PY2IOP_CMD_OFFSET) == 0):
                pass

            # Read the samples from ADC
            readings=[]
            if (ch1):
                readings.append(self.mmio.read(iop_const.MAILBOX_OFFSET))
            if (ch2):
                readings.append(self.mmio.read(iop_const.MAILBOX_OFFSET+4))
            if (ch3):
                readings.append(self.mmio.read(iop_const.MAILBOX_OFFSET+8))
            return readings

        def read(self, ch1=1, ch2=0, ch3=0):
            """Get the voltage from the Pmod ADC.

            When ch1, ch2, and ch3 values are 1 then the corresponding channel
            is included.

            For each channel selected, this method reads and returns one sample.

            Note
            ----
            The 4th channel is not available due to the jumper setting on ADC.

            Note
            ----
            This method reads the voltage values from ADC.

            Parameters
            ----------
            ch1 : int
                1 means include channel 1, 0 means do not include.
            ch2 : int
                1 means include channel 2, 0 means do not include.
            ch3 : int
                1 means include channel 3, 0 means do not include.

            Returns
            -------
            list
                The voltage values read from the 3 channels of the Pmod ADC.

            """
            if (ch1 not in range(2)):
                raise ValueError("Valid value for ch1 is 0 or 1.")
            if (ch2 not in range(2)):
                raise ValueError("Valid value for ch2 is 0 or 1.")
            if (ch3 not in range(2)):
                raise ValueError("Valid value for ch3 is 0 or 1.")
            cmd= (ch3 << 6) | (ch2 << 5) | (ch1 << 4) | 5

            # Send the command
            self.mmio.write(iop_const.MAILBOX_OFFSET +
                            iop_const.MAILBOX_PY2IOP_CMD_OFFSET, cmd)

            # Wait for I/O processor to complete
            while not (self.mmio.read(iop_const.MAILBOX_OFFSET +
                                  iop_const.MAILBOX_PY2IOP_CMD_OFFSET) == 0):
                pass

            # Read the last sample from ADC
            readings=[]
            if (ch1):
                readings.append(self._reg2float(self.mmio.read(
                                            iop_const.MAILBOX_OFFSET)))
            if (ch2):
                readings.append(self._reg2float(self.mmio.read(
                                            iop_const.MAILBOX_OFFSET+4)))
            if (ch3):
                readings.append(self._reg2float(self.mmio.read(
                                            iop_const.MAILBOX_OFFSET+8)))
            return readings

        def start_log_raw(self, ch1=1, ch2=0, ch3=0, log_interval_us=100):
            """Start the log of raw values with the interval specified.

            This parameter `log_interval_us` can set the time interval between
            two samples, so that users can read out multiple values in a single
            log.

            Parameters
            ----------
            ch1 : int
                1 means include channel 1, 0 means do not include.
            ch2 : int
                1 means include channel 2, 0 means do not include.
            ch3 : int
                1 means include channel 3, 0 means do not include.
            log_interval_us : int
                The length of the log in milliseconds, for debug only.

            Returns
            -------
            None

            """
            if (log_interval_us < 0):
                raise ValueError("Time between samples should be no less than 0.")
            if (ch1 not in range(2)):
                raise ValueError("Valid value for ch1 is 0 or 1.")
            if (ch2 not in range(2)):
                raise ValueError("Valid value for ch2 is 0 or 1.")
            if (ch3 not in range(2)):
                raise ValueError("Valid value for ch3 is 0 or 1.")

            cmd= (ch3 << 6) | (ch2 << 5) | (ch1 << 4) | 7

            self.log_running = 1

            # Send log interval
            self.mmio.write(iop_const.MAILBOX_OFFSET, log_interval_us)

            # Send the command
            self.mmio.write(iop_const.MAILBOX_OFFSET+\
                            iop_const.MAILBOX_PY2IOP_CMD_OFFSET, cmd)

        def start_log(self, ch1=1, ch2=0, ch3=0, log_interval_us=100):
            """Start the log of voltage values with the interval specified.

            This parameter `log_interval_us` can set the time interval between
            two samples, so that users can read out multiple values in a single
            log.

            Parameters
            ----------
            ch1 : int
                1 means include channel 1, 0 means do not include.
            ch2 : int
                1 means include channel 2, 0 means do not include.
            ch3 : int
                1 means include channel 3, 0 means do not include.
            log_interval_us : int
                The length of the log in milliseconds, for debug only.

            Returns
            -------
            None

            """
            if (log_interval_us < 0):
                raise ValueError("Time between samples should be no less than 0.")
            if (ch1 not in range(2)):
                raise ValueError("Valid value for ch1 is 0 or 1.")
            if (ch2 not in range(2)):
                raise ValueError("Valid value for ch2 is 0 or 1.")
            if (ch3 not in range(2)):
                raise ValueError("Valid value for ch3 is 0 or 1.")

            cmd= (ch3 << 6) | (ch2 << 5) | (ch1 << 4) | 9

            self.log_running = 1

            # Send log interval and the channel number
            self.mmio.write(iop_const.MAILBOX_OFFSET, log_interval_us)

            # Send the command
            self.mmio.write(iop_const.MAILBOX_OFFSET+\
                            iop_const.MAILBOX_PY2IOP_CMD_OFFSET, cmd)

        def stop_log_raw(self):
            """Stop the log of raw values.

            This is done by sending the reset command to IOP. There is no need to
            wait for the IOP.

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

            Returns
            -------
            None

            """
            if(self.log_running == 1):
                self.mmio.write(iop_const.MAILBOX_OFFSET+\
                            iop_const.MAILBOX_PY2IOP_CMD_OFFSET, 0x1)
                self.log_running = 0
            else:
                raise RuntimeError("No grove ADC log running.")

        def stop_log(self):
            """Stop the log of voltage values.

            This is done by sending the reset command to IOP. There is no need to
            wait for the IOP.

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

            Returns
            -------
            None

            """
            if(self.log_running == 1):
                self.mmio.write(iop_const.MAILBOX_OFFSET+\
                            iop_const.MAILBOX_PY2IOP_CMD_OFFSET, 0x1)
                self.log_running = 0
            else:
                raise RuntimeError("No grove ADC log running.")

        def get_log_raw(self):
            """Get the log of raw values.

            First stop the log before getting the log.

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

            Returns
            -------
            list
                List of raw samples from the ADC.

            """
            # Stop logging
            self.stop_log_raw()

            # Prep iterators and results list
            head_ptr = self.mmio.read(iop_const.MAILBOX_OFFSET+0x8)
            tail_ptr = self.mmio.read(iop_const.MAILBOX_OFFSET+0xC)
            readings = list()

            # Sweep circular buffer for samples
            if head_ptr == tail_ptr:
                return None
            elif head_ptr < tail_ptr:
                for i in range(head_ptr,tail_ptr,4):
                    readings.append(self.mmio.read(i))
            else:
                for i in range(head_ptr,PMOD_ADC_LOG_END,4):
                    readings.append(self.mmio.read(i))
                for i in range(PMOD_ADC_LOG_START,tail_ptr,4):
                    readings.append(self.mmio.read(i))
            return readings

        def get_log(self):
            """Get the log of voltage values.

            First stop the log before getting the log.

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

            Returns
            -------
            list
                List of voltage samples from the ADC.

            """
            # Stop logging
            self.stop_log()

            # Prep iterators and results list
            head_ptr = self.mmio.read(iop_const.MAILBOX_OFFSET+0x8)
            tail_ptr = self.mmio.read(iop_const.MAILBOX_OFFSET+0xC)
            readings = list()

            # Sweep circular buffer for samples
            if head_ptr == tail_ptr:
                return None
            elif head_ptr < tail_ptr:
                for i in range(head_ptr,tail_ptr,4):
                    readings.append(float("{0:.4f}"\
                        .format(self._reg2float(self.mmio.read(i)))))
            else:
                for i in range(head_ptr,PMOD_ADC_LOG_END,4):
                    readings.append(float("{0:.4f}"\
                        .format(self._reg2float(self.mmio.read(i)))))
                for i in range(PMOD_ADC_LOG_START,tail_ptr,4):
                    readings.append(float("{0:.4f}"\
                        .format(self._reg2float(self.mmio.read(i)))))
            return readings

        def _reg2float(self, reg):
            """Converts 32-bit register value to floats in Python.

            Parameters
            ----------
            reg: int
                A 32-bit register value read from the mailbox.

            Returns
            -------
            float
                A float number translated from the register value.

            """
            s = struct.pack('>l', reg)
            return round(struct.unpack('>f', s)[0], 4)