Added typing and missing CP7 functions

[hackapet/Adafruit_Blinka_Displayio.git] / displayio / _i2cdisplay.py

diff --git a/displayio/_i2cdisplay.py b/displayio/_i2cdisplay.py
new file mode 100644 (file)
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+++ b/displayio/_i2cdisplay.py
@@ -0,0 +1,110 @@
+# SPDX-FileCopyrightText: 2020 Melissa LeBlanc-Williams for Adafruit Industries
+# SPDX-FileCopyrightText: 2020 Erik Tollerud
+# SPDX-FileCopyrightText: 2021 Jim Morris
+# SPDX-FileCopyrightText: 2021 James Carr
+#
+# SPDX-License-Identifier: MIT
+
+"""
+`displayio.i2cdisplay`
+================================================================================
+
+displayio for Blinka
+
+**Software and Dependencies:**
+
+* Adafruit Blinka:
+  https://github.com/adafruit/Adafruit_Blinka/releases
+
+* Author(s): Melissa LeBlanc-Williams, Erik Tollerud, James Carr
+
+"""
+
+import time
+import busio
+import digitalio
+import _typing
+from ._constants import CHIP_SELECT_UNTOUCHED, DISPLAY_COMMAND
+
+__version__ = "0.0.0-auto.0"
+__repo__ = "https://github.com/adafruit/Adafruit_Blinka_displayio.git"
+
+
+class I2CDisplay:
+    """Manage updating a display over I2C in the background while Python code runs.
+    It doesn’t handle display initialization.
+    """
+
+    def __init__(self, i2c_bus: busio.I2C, *, device_address: int, reset=None):
+        """Create a I2CDisplay object associated with the given I2C bus and reset pin.
+
+        The I2C bus and pins are then in use by the display until displayio.release_displays() is
+        called even after a reload. (It does this so CircuitPython can use the display after your
+        code is done.) So, the first time you initialize a display bus in code.py you should call
+        :py:func`displayio.release_displays` first, otherwise it will error after the first
+        code.py run.
+        """
+
+        if reset is not None:
+            self._reset = digitalio.DigitalInOut(reset)
+            self._reset.switch_to_output(value=True)
+        else:
+            self._reset = None
+        self._i2c = i2c_bus
+        self._dev_addr = device_address
+
+    def _release(self):
+        self.reset()
+        self._i2c.deinit()
+        if self._reset is not None:
+            self._reset.deinit()
+
+    def reset(self) -> None:
+        """
+        Performs a hardware reset via the reset pin if one is present.
+        """
+
+        if self._reset is None:
+            return
+
+        self._reset.value = False
+        time.sleep(0.0001)
+        self._reset.value = True
+
+    def _begin_transaction(self) -> None:
+        """Lock the bus before sending data."""
+        while not self._i2c.try_lock():
+            pass
+
+    def send(self, command: int, data: _typing.ReadableBuffer) -> None:
+        """
+        Sends the given command value followed by the full set of data. Display state,
+        such as vertical scroll, set via ``send`` may or may not be reset once the code is
+        done.
+        """
+        self._begin_transaction()
+        self._send(DISPLAY_COMMAND, CHIP_SELECT_UNTOUCHED, bytes([command] + data))
+        self._end_transaction()
+
+    # pylint: disable=unused-argument
+    def _send(self, data_type: int, chip_select: int, data: _typing.ReadableBuffer):
+        if data_type == DISPLAY_COMMAND:
+            n = len(data)
+            if n > 0:
+                command_bytes = bytearray(n * 2)
+                for i in range(n):
+                    command_bytes[2 * i] = 0x80
+                    command_bytes[2 * i + 1] = data[i]
+
+                self._i2c.writeto(self._dev_addr, buffer=command_bytes, stop=True)
+        else:
+            data_bytes = bytearray(len(data) + 1)
+            data_bytes[0] = 0x40
+            data_bytes[1:] = data
+            self._i2c.writeto(self._dev_addr, buffer=data_bytes, stop=True)
+
+    # pylint: enable=unused-argument
+
+    def _end_transaction(self) -> None:
+        """Release the bus after sending data."""
+        self._i2c.unlock()