Source code for pynq.lib.axigpio

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import asyncio
from pynq import DefaultIP


__author__ = "Peter Ogden"
__copyright__ = "Copyright 2017, Xilinx"
__email__ = "pynq_support@xilinx.com"


[docs]class AxiGPIO(DefaultIP): """Class for interacting with the AXI GPIO IP block. This class exposes the two banks of GPIO as the `channel1` and `channel2` attributes. Each channel can have the direction and the number of wires specified. The wires in the channel can be accessed from the channel using slice notation - all slices must have a stride of 1. Input wires can be `read` and output wires can be written to, toggled, or turned off or on. InOut channels combine the functionality of input and output channels. The tristate of the pin is determined by whether the pin was last read or written. """
[docs] class Input: """Class representing wires in an input channel. This class should be passed to `setdirection` to indicate the channel should be used for input only. It should not be used directly. """ def __init__(self, parent, start, stop): self._parent = parent self._start = start self._stop = stop self._mask = (1 << (stop - start)) - 1
[docs] def read(self): """Reads the value of all the wires in the slice If there is more than one wire in the slice then the least significant bit of the return value corresponds to the wire with the lowest index. """ return (self._parent.read() >> self._start) & self._mask
[docs] @asyncio.coroutine def wait_for_value_async(self, value): """Coroutine that waits until the specified value is read This function relies on interrupts being available for the IP block and will throw a `RuntimeError` otherwise. """ while self.read() != value: yield from self._parent.wait_for_interrupt_async()
[docs] def wait_for_value(self, value): """Wait until the specified value is read This function is dependent on interrupts being enabled and will throw a `RuntimeError` otherwise. Internally it uses asyncio so should not be used inside an asyncio task. Use `wait_for_value_async` if using asyncio. """ loop = asyncio.get_event_loop() loop.run_until_complete(asyncio.ensure_future( self.wait_for_value_async(value) ))
[docs] class Output: """Class representing wires in an output channel. This class should be passed to `setdirection` to indicate the channel should be used for output only. It should not be used directly. """ def __init__(self, parent, start, stop): self._parent = parent self._start = start self._stop = stop self._mask = (1 << (stop - start)) - 1
[docs] def read(self): """Reads the value of all the wires in the slice If there is more than one wire in the slice then the least significant bit of the return value corresponds to the wire with the lowest index. """ return (self._parent._val >> self._start) & self._mask
[docs] def write(self, val): """Set the value of the slice If the slice consists of more than one wire then the least significant bit of `val` corresponds to the lowest index wire. """ if val > self._mask: raise ValueError("{} too large for {} bits" .format(val, self._stop - self._start)) self._parent.write(val << self._start, self._mask << self._start)
[docs] def on(self): """Turns on all of the wires in the slice """ self.write(self._mask)
[docs] def off(self): """Turns off all of the wires in the slice """ self.write(0)
[docs] def toggle(self): """Toggles all of the wires in the slice """ self.write((~self._parent.val >> self._start) & self._mask)
[docs] class InOut(Output, Input): """Class representing wires in an inout channel. This class should be passed to `setdirection` to indicate the channel should be used for both input and output. It should not be used directly. """ def __init__(self, parent, start, stop): self._parent = parent self._start = start self._stop = stop self._mask = (1 << (stop - start)) - 1 self._trimask = self._mask << start
[docs] def read(self): """Reads the value of all the wires in the slice Changes the tristate of the slice to input. If there is more than one wire in the slice then the least significant bit of the return value corresponds to the wire with the lowest index. """ self._parent.trimask |= self._trimask return super().read()
[docs] def write(self, val): """Set the value of the slice Changes the tristate of the slice to output. If the slice consists of more than one wire then the least significant bit of `val` corresponds to the lowest index wire. """ self._parent.trimask &= ~self._trimask return super().write(val)
[docs] class Channel: """Class representing a single channel of the GPIO controller. Wires are and bundles of wires can be accessed using array notation with the methods on the wires determined by the type of the channel:: input_channel[0].read() output_channel[1:3].on() This class instantiated not used directly, instead accessed through the `AxiGPIO` classes attributes. This class exposes the wires connected to the channel as an array or elements. Slices of the array can be assigned simultaneously. """ def __init__(self, parent, channel): self._parent = parent self._channel = channel self.slicetype = AxiGPIO.InOut self.length = 32 self.val = 0 self._waiter_count = 0 def __getitem__(self, idx): if isinstance(idx, slice): if idx.step is not None and idx.step != 1: raise IndexError("Steps other than 1 not supported") return self.slicetype(self, idx.start, idx.stop) elif isinstance(idx, int): if idx >= self.length: raise IndexError() return self.slicetype(self, idx, idx + 1) def __len__(self): return self.length
[docs] def write(self, val, mask): """Set the state of the output pins """ self.val = (self.val & ~mask) | (val & mask) self._parent.write(self._channel * 8, self.val)
[docs] def read(self): """Read the state of the input pins """ return self._parent.read(self._channel * 8)
@property def trimask(self): """Gets or sets the tri-state mask for an inout channel """ return self._parent.read(self._channel * 8 + 4) @trimask.setter def trimask(self, value): self._parent.write(self._channel * 8 + 4, value)
[docs] def setlength(self, length): """Set the number of wires connected to the channel """ self.length = length
[docs] def setdirection(self, direction): """Set the direction of the channel Must be one of AxiGPIO.{Input, Output, InOut} or the string 'in', 'out', or 'inout' """ if type(direction) is str: if direction in _direction_map: direction = _direction_map[direction] if direction not in [AxiGPIO.Input, AxiGPIO.Output, AxiGPIO.InOut]: raise ValueError( "direction should be one of AxiGPIO.{Input,Output,InOut} " "or the string 'in', 'out' or 'inout'") self.slicetype = direction
[docs] @asyncio.coroutine def wait_for_interrupt_async(self): """Wait for the interrupt on the channel to be signalled This is intended to be used by slices waiting for a particular value but can be used in any situation to wait for a per-channel interrupt. """ if not self._parent.has_interrupts: raise RuntimeError('Interrupts not available for this IP') mask = (1 << self._channel) if self._waiter_count == 0: enable = self._parent.read(0x128) enable |= mask self._parent.write(0x128, enable) self._waiter_count += 1 yield from self._parent.ip2intc_irpt.wait() if self._parent.read(0x120) & mask: self._parent.write(0x120, mask) self._waiter_count -= 1 if self._waiter_count == 0: enable = self._parent.read(0x128) enable &= ~mask self._parent.write(0x128, enable)
def __init__(self, description): super().__init__(description) self._channels = [AxiGPIO.Channel(self, i) for i in range(2)] self.channel1 = self._channels[0] self.channel2 = self._channels[1] if 'ip2intc_irpt' in description['interrupts']: self.write(0x11C, 0x80000000) self.has_interrupts = True else: self.has_interrupts = False
[docs] def setlength(self, length, channel=1): """Sets the length of a channel in the controller """ self._channels[channel - 1].length = length
[docs] def setdirection(self, direction, channel=1): """Sets the direction of a channel in the controller Must be one of AxiGPIO.{Input, Output, InOut} or the string 'in', 'out' or 'inout' """ if direction not in [AxiGPIO.Input, AxiGPIO.Output, AxiGPIO.InOut]: raise ValueError( "direction should be one of AxiGPIO.{Input,Output,InOut}") self._channels[channel - 1].slicetype = direction
def __getitem__(self, idx): return self.channel1[idx] bindto = ['xilinx.com:ip:axi_gpio:2.0']
_direction_map = { "in": AxiGPIO.Input, "out": AxiGPIO.Output, "inout": AxiGPIO.InOut }