Merge pull request #160 from dastels/master

ladyada · web-flow · commit 9016d1dbe198 · 2018-05-12T23:27:58.000-04:00
Add code for Astels' "Digital Circuits 6: EPROM Emulator" project guide
diff --git a/EPROM_Emulator/LICENSE.md b/EPROM_Emulator/LICENSE.md
@@ -0,0 +1,22 @@
+
+The MIT License (MIT)
+
+Copyright (c) 2018 
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/EPROM_Emulator/README.md b/EPROM_Emulator/README.md
@@ -0,0 +1,3 @@
+# 2716 Eprom Emulator
+
+This code goes along with the Digital Circuits 6: An EPROM Emulator learnign guide.
diff --git a/EPROM_Emulator/debouncer.py b/EPROM_Emulator/debouncer.py
@@ -0,0 +1,105 @@
+"""
+The MIT License (MIT)
+
+Copyright (c) 2018 Dave Astels
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+--------------------------------------------------------------------------------
+Debounce an input pin.
+"""
+
+import time
+import digitalio
+
+class Debouncer(object):
+    """Debounce an input pin"""
+
+    DEBOUNCED_STATE = 0x01
+    UNSTABLE_STATE = 0x02
+    CHANGED_STATE = 0x04
+
+
+    def __init__(self, pin, mode=None, interval=0.010):
+        """Make am instance.
+           :param int pin: the pin (from board) to debounce
+           :param int mode: digitalio.Pull.UP or .DOWN (default is no pull up/down)
+           :param int interval: bounce threshold in seconds (default is 0.010, i.e. 10 milliseconds)
+        """
+        self.state = 0x00
+        self.pin = digitalio.DigitalInOut(pin)
+        self.pin.direction = digitalio.Direction.INPUT
+        if mode != None:
+            self.pin.pull = mode
+        if self.pin.value:
+            self.__set_state(Debouncer.DEBOUNCED_STATE | Debouncer.UNSTABLE_STATE)
+        self.previous_time = 0
+        if interval is None:
+            self.interval = 0.010
+        else:
+            self.interval = interval
+
+
+    def __set_state(self, bits):
+        self.state |= bits
+
+
+    def __unset_state(self, bits):
+        self.state &= ~bits
+
+
+    def __toggle_state(self, bits):
+        self.state ^= bits
+
+
+    def __get_state(self, bits):
+        return (self.state & bits) != 0
+
+
+    def update(self):
+        """Update the debouncer state. Must be called before using any of the properties below"""
+        self.__unset_state(Debouncer.CHANGED_STATE)
+        current_state = self.pin.value
+        if current_state != self.__get_state(Debouncer.UNSTABLE_STATE):
+            self.previous_time = time.monotonic()
+            self.__toggle_state(Debouncer.UNSTABLE_STATE)
+        else:
+            if time.monotonic() - self.previous_time >= self.interval:
+                if current_state != self.__get_state(Debouncer.DEBOUNCED_STATE):
+                    self.previous_time = time.monotonic()
+                    self.__toggle_state(Debouncer.DEBOUNCED_STATE)
+                    self.__set_state(Debouncer.CHANGED_STATE)
+
+
+    @property
+    def value(self):
+        """Return the current debounced value of the input."""
+        return self.__get_state(Debouncer.DEBOUNCED_STATE)
+
+
+    @property
+    def rose(self):
+        """Return whether the debounced input went from low to high at the most recent update."""
+        return self.__get_state(self.DEBOUNCED_STATE) and self.__get_state(self.CHANGED_STATE)
+
+
+    @property
+    def fell(self):
+        """Return whether the debounced input went from high to low at the most recent update."""
+        return (not self.__get_state(self.DEBOUNCED_STATE)) and self.__get_state(self.CHANGED_STATE)
diff --git a/EPROM_Emulator/directory_node.py b/EPROM_Emulator/directory_node.py
@@ -0,0 +1,202 @@
+"""
+The MIT License (MIT)
+
+Copyright (c) 2018 Dave Astels
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+--------------------------------------------------------------------------------
+
+Manage a directory in the file system.
+"""
+
+import os
+
+class DirectoryNode(object):
+    """Display and navigate the SD card contents"""
+
+    def __init__(self, display, parent=None, name="/"):
+        """Initialize a new instance.
+           :param adafruit_ssd1306.SSD1306 on: the OLED instance to display on
+           :param DirectoryNode below: optional parent directory node
+           :param string named: the optional name of the new node
+        """
+        self.display = display
+        self.parent = parent
+        self.name = name
+        self.files = []
+        self.top_offset = 0
+        self.old_top_offset = -1
+        self.selected_offset = 0
+        self.old_selected_offset = -1
+
+
+    def __cleanup(self):
+        """Dereference things for speedy gc."""
+        self.display = None
+        self.parent = None
+        self.name = None
+        self.files = None
+        return self
+
+
+    def __is_dir(self, path):
+        """Determine whether a path identifies a machine code bin file.
+           :param string path: path of the file to check
+        """
+        if path[-2:] == "..":
+            return False
+        try:
+            os.listdir(path)
+            return True
+        except OSError:
+            return False
+
+
+    def __sanitize(self, name):
+        """Nondestructively strip off a trailing slash, if any, and return the result.
+           :param string name: the filename
+        """
+        if name[-1] == "/":
+            return name[:-1]
+        return name
+
+
+    def __path(self):
+        """Return the result of recursively follow the parent links, building a full
+           path to this directory."""
+        if self.parent:
+            return self.parent.__path() + os.sep + self.__sanitize(self.name)
+        return self.__sanitize(self.name)
+
+
+    def __make_path(self, filename):
+        """Return a full path to the specified file in this directory.
+           :param string filename: the name of the file in this directory
+         """
+        return self.__path() + os.sep + filename
+
+
+    def __number_of_files(self):
+        """The number of files in this directory, including the ".." for the parent
+            directory if this isn't the top directory on the SD card."""
+        self.__get_files()
+        return len(self.files)
+
+
+    def __get_files(self):
+        """Return a list of the files in this directory.
+           If this is not the top directory on the SD card, a ".." entry is the first element.
+           Any directories have a slash appended to their name."""
+        if len(self.files) == 0:
+            self.files = os.listdir(self.__path())
+            self.files.sort()
+            if self.parent:
+                self.files.insert(0, "..")
+            for index, name in enumerate(self.files, start=1):
+                if self.__is_dir(self.__make_path(name)):
+                    self.files[index] = name + "/"
+
+
+    def __update_display(self):
+        """Update the displayed list of files if required."""
+        if self.top_offset != self.old_top_offset:
+            self.__get_files()
+            self.display.fill(0)
+            for i in range(self.top_offset, min(self.top_offset + 4, self.__number_of_files())):
+                self.display.text(self.files[i], 10, (i - self.top_offset) * 8)
+            self.display.show()
+            self.old_top_offset = self.top_offset
+
+
+    def __update_selection(self):
+        """Update the selected file lighlight if required."""
+        if self.selected_offset != self.old_selected_offset:
+            if self.old_selected_offset > -1:
+                self.display.text(">", 0, (self.old_selected_offset - self.top_offset) * 8, 0)
+            self.display.text(">", 0, (self.selected_offset - self.top_offset) * 8, 1)
+            self.display.show()
+            self.old_selected_offset = self.selected_offset
+
+
+    def __is_directory_name(self, filename):
+        """Is a filename the name of a directory.
+           :param string filename: the name of the file
+        """
+        return filename[-1] == '/'
+
+
+    @property
+    def selected_filename(self):
+        """The name of the currently selected file in this directory."""
+        self.__get_files()
+        return self.files[self.selected_offset]
+
+
+    @property
+    def selected_filepath(self):
+        """The full path of the currently selected file in this directory."""
+        return self.__make_path(self.selected_filename)
+
+
+    def force_update(self):
+        """Force an update of the file list and selected file highlight."""
+        self.old_selected_offset = -1
+        self.old_top_offset = -1
+        self.__update_display()
+        self.__update_selection()
+
+
+    def down(self):
+        """Move down in the file list if possible, adjusting the selected file indicator
+           and scrolling the display as required."""
+        if self.selected_offset < self.__number_of_files() - 1:
+            self.selected_offset += 1
+            if self.selected_offset == self.top_offset + 4:
+                self.top_offset += 1
+                self.__update_display()
+        self.__update_selection()
+
+
+    def up(self):
+        """Move up in the file list if possible, adjusting the selected file indicator
+           and scrolling the display as required."""
+        if self.selected_offset > 0:
+            self.selected_offset -= 1
+            if self.selected_offset < self.top_offset:
+                self.top_offset -= 1
+                self.__update_display()
+        self.__update_selection()
+
+
+    def click(self):
+        """Handle a selection and return the new current directory.
+           If the selected file is the parent, i.e. "..", return to the parent directory.
+           If the selected file is a directory, go into it."""
+        if self.selected_filename == "..":
+            if self.parent:
+                p = self.parent
+                p.force_update()
+                self.__cleanup()
+                return p
+        elif self.__is_directory_name(self.selected_filename):
+            new_node = DirectoryNode(self.display, self, self.selected_filename)
+            new_node.force_update()
+            return new_node
+        return self
diff --git a/EPROM_Emulator/emulator.py b/EPROM_Emulator/emulator.py
diff --git a/EPROM_Emulator/main.py b/EPROM_Emulator/main.py

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+# 2716 Eprom Emulator`
	`2`	`+`
	`3`	`+This code goes along with the Digital Circuits 6: An EPROM Emulator learnign guide.`