# Copyright (c) 2016, Xilinx, Inc.
# SPDX-License-Identifier: BSD-3-Clause
import asyncio
from pynq import DefaultIP
[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 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(Input, Output):
"""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"""
if self.slicetype == AxiGPIO.Input:
raise RuntimeError("You cannot write to an Input")
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"""
if self.slicetype == AxiGPIO.Output:
raise RuntimeError("You cannot read from an output")
return self._parent.read(self._channel * 8)
@property
def trimask(self):
"""Gets or sets the tristate 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] async 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
await 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 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}")
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}