Split module into multiple files

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

diff --git a/displayio/fourwire.py b/displayio/fourwire.py
new file mode 100644 (file)
index 0000000..80b15d9
--- /dev/null
+++ b/displayio/fourwire.py
@@ -0,0 +1,122 @@
+# The MIT License (MIT)
+#
+# Copyright (c) 2020 Melissa LeBlanc-Williams for Adafruit Industries
+#
+# 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.
+
+"""
+`displayio`
+================================================================================
+
+displayio for Blinka
+
+**Software and Dependencies:**
+
+* Adafruit Blinka:
+  https://github.com/adafruit/Adafruit_Blinka/releases
+
+* Author(s): Melissa LeBlanc-Williams
+
+"""
+
+import time
+import digitalio
+
+__version__ = "0.0.0-auto.0"
+__repo__ = "https://github.com/adafruit/Adafruit_Blinka_displayio.git"
+
+
+class FourWire:
+    """Manage updating a display over SPI four wire protocol in the background while
+    Python code runs. It doesn’t handle display initialization.
+    """
+
+    def __init__(
+        self,
+        spi_bus,
+        *,
+        command,
+        chip_select,
+        reset=None,
+        baudrate=24000000,
+        polarity=0,
+        phase=0
+    ):
+        """Create a FourWire object associated with the given pins.
+
+        The SPI 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.
+        """
+        self._dc = digitalio.DigitalInOut(command)
+        self._dc.switch_to_output()
+        self._chip_select = digitalio.DigitalInOut(chip_select)
+        self._chip_select.switch_to_output(value=True)
+
+        if reset is not None:
+            self._reset = digitalio.DigitalInOut(reset)
+            self._reset.switch_to_output(value=True)
+        else:
+            self._reset = None
+        self._spi = spi_bus
+        while self._spi.try_lock():
+            pass
+        self._spi.configure(baudrate=baudrate, polarity=polarity, phase=phase)
+        self._spi.unlock()
+
+    def _release(self):
+        self.reset()
+        self._spi.deinit()
+        self._dc.deinit()
+        self._chip_select.deinit()
+        if self._reset is not None:
+            self._reset.deinit()
+
+    def reset(self):
+        """Performs a hardware reset via the reset pin.
+        Raises an exception if called when no reset pin is available.
+        """
+        if self._reset is not None:
+            self._reset.value = False
+            time.sleep(0.001)
+            self._reset.value = True
+            time.sleep(0.001)
+        else:
+            raise RuntimeError("No reset pin defined")
+
+    def send(self, is_command, data, *, toggle_every_byte=False):
+        """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.
+        """
+        while self._spi.try_lock():
+            pass
+        self._dc.value = not is_command
+        if toggle_every_byte:
+            for byte in data:
+                self._spi.write(bytes([byte]))
+                self._chip_select.value = True
+                time.sleep(0.000001)
+                self._chip_select.value = False
+        else:
+            self._spi.write(data)
+        self._spi.unlock()