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[Adafruit_Blinka-hackapet.git] / src / adafruit_blinka / microcontroller / fake_mcp2221 / pin.py

diff --git a/src/adafruit_blinka/microcontroller/fake_mcp2221/pin.py b/src/adafruit_blinka/microcontroller/fake_mcp2221/pin.py
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+# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+"""fake_mcp2221 pin names"""
+import random
+from .fake_mcp2221 import mcp2221
+
+
+class Pin:
+    """A basic Pin class for use with a "fake" MCP2221."""
+
+    # pin modes
+    OUT = 0
+    IN = 1
+    ADC = 2
+    DAC = 3
+    # pin values
+    LOW = 0
+    HIGH = 1
+
+    def __init__(self, pin_id=None):
+        self.id = pin_id
+        self._mode = None
+        self._prv_val = None
+
+    def init(self, mode=IN, pull=None):
+        """Initialize the Pin"""
+        if self.id is None:
+            raise RuntimeError("Can not init a None type pin.")
+        if pull is not None:
+            raise NotImplementedError("Internal pullups and pulldowns not supported on the MCP2221")
+        if mode in (Pin.IN, Pin.OUT):
+            # All pins can do GPIO
+            pass
+        elif mode == Pin.ADC:
+            # ADC only available on these pins
+            if self.id not in (1, 2, 3):
+                raise ValueError("Pin does not have ADC capabilities")
+            pass
+            # Do nothing
+        elif mode == Pin.DAC:
+            # DAC only available on these pins
+            if self.id not in (2, 3):
+                raise ValueError("Pin does not have DAC capabilities")
+            pass
+        else:
+            raise ValueError("Incorrect pin mode: {}".format(mode))
+        self._mode = mode
+
+    def value(self, val=None):
+        """Set or return the Pin Value"""
+        # Digital In / Out
+        if self._mode in (Pin.IN, Pin.OUT):
+            # digital read
+            if val is None:
+                # The value returned will toggle between True and False
+                # and will be True on the first digital read
+                # TODO: Behavior needs to be tested
+                if self._prv_val == None or False:
+                    self._prv_val = True
+                else:
+                    self._prv_val = False
+                return self._prv_val
+            # digital write
+            if val in (Pin.LOW, Pin.HIGH):
+                # We don't need to do anything here - no data is produced
+                return None
+            # nope
+            raise ValueError("Invalid value for pin.")
+        # Analog In
+        if self._mode == Pin.ADC:
+            if val is None:
+                # Returned value is between 0 and 65535 inclusive
+                # https://docs.circuitpython.org/en/latest/shared-bindings/analogio/index.html#analogio.AnalogIn.value
+                self._prv_val = random.randint(0, 65535)
+                return self._prv_val
+            # read only
+            raise AttributeError("'AnalogIn' object has no attribute 'value'")
+        # Analog Out
+        if self._mode == Pin.DAC:
+            if val is None:
+                # write only
+                raise AttributeError("unreadable attribute")
+            # We don't write to the DAC as this is a "fake" implementation
+            return None
+        raise RuntimeError(
+            "No action for mode {} with value {}".format(self._mode, val)
+        )
+
+
+# create pin instances for each pin
+G0 = Pin(0)
+G1 = Pin(1)
+G2 = Pin(2)
+G3 = Pin(3)
+
+SCL = Pin()
+SDA = Pin()
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