+++ /dev/null
-# SPDX-FileCopyrightText: 2020 Melissa LeBlanc-Williams for Adafruit Industries
-#
-# SPDX-License-Identifier: MIT
-
-"""
-`displayio.fourwire`
-================================================================================
-
-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(value=False)
- self._chip_select = digitalio.DigitalInOut(chip_select)
- self._chip_select.switch_to_output(value=True)
- self._frequency = baudrate
- self._polarity = polarity
- self._phase = phase
-
- 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
-
- 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)
-
- 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.
- """
- 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)
-
- def begin_transaction(self):
- """Begin the SPI transaction by locking, configuring, and setting Chip Select"""
- while not self._spi.try_lock():
- pass
- self._spi.configure(
- baudrate=self._frequency, polarity=self._polarity, phase=self._phase
- )
- self._chip_select.value = False
-
- def end_transaction(self):
- """End the SPI transaction by unlocking and setting Chip Select"""
- self._chip_select.value = True
- self._spi.unlock()