make optimizations in case we dont have to toggle CS pin on each write.

also add examples for u2if versions of feather epd

adafruit_epd/epd.py

@@ -107,8 +107,7 @@ class Adafruit_EPD:  # pylint: disable=too-many-instance-attributes, too-many-pu
                 databyte = self._spi_transfer(databyte)
             self.sram.cs_pin.value = True
         else:
-            for databyte in self._buffer1:
-                self._spi_transfer(databyte)
+            self._spi_transfer(self._buffer1)
 
         self._cs.value = True
         self.spi_device.unlock()
@@ -140,8 +139,7 @@ class Adafruit_EPD:  # pylint: disable=too-many-instance-attributes, too-many-pu
                     databyte = self._spi_transfer(databyte)
                 self.sram.cs_pin.value = True
             else:
-                for databyte in self._buffer2:
-                    self._spi_transfer(databyte)
+                self._spi_transfer(self._buffer2)
 
             self._cs.value = True
             self.spi_device.unlock()
@@ -171,23 +169,39 @@ class Adafruit_EPD:  # pylint: disable=too-many-instance-attributes, too-many-pu
 
         if data is not None:
             self._dc.value = True
-            for b in data:
-                self._spi_transfer(b)
+            self._spi_transfer(data)
         if end:
             self._cs.value = True
         self.spi_device.unlock()
 
         return ret
 
-    def _spi_transfer(self, databyte):
-        """Transfer one byte, toggling the cs pin if required by the EPD chipset"""
-        self._spibuf[0] = databyte
-        if self._single_byte_tx:
-            self._cs.value = False
-        self.spi_device.write_readinto(self._spibuf, self._spibuf)
-        if self._single_byte_tx:
-            self._cs.value = True
-        return self._spibuf[0]
+    def _spi_transfer(self, data):
+        """Transfer one byte or bytearray, toggling the cs pin if required by the EPD chipset"""
+        if isinstance(data, int): # single byte!
+            self._spibuf[0] = data
+
+        # easy & fast case: array and no twiddling
+        if not self._single_byte_tx and isinstance(data, bytearray):
+            self.spi_device.write(data)
+            return None
+
+        # if its a single byte
+        if isinstance(data, int): # single byte!
+            if self._single_byte_tx:
+                self._cs.value = False
+            try:
+                self.spi_device.write_readinto(self._spibuf, self._spibuf)
+            except NotImplementedError:
+                self.spi_device.write(self._spibuf)
+            if self._single_byte_tx:
+                self._cs.value = True
+            return self._spibuf[0]
+
+        if isinstance(data, bytearray):
+            for x in data:
+                self._spi_transfer(x)
+        return None
 
     def power_up(self):
         """Power up the display in preparation for writing RAM and updating.

examples/feather_epd_blinka.py

@@ -0,0 +1,33 @@
+# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+import digitalio
+import busio
+import board
+from adafruit_epd.epd import Adafruit_EPD
+import time
+
+# create the spi device and pins we will need
+spi = busio.SPI(board.EPD_SCK, MOSI=board.EPD_MOSI, MISO=None)
+epd_cs = digitalio.DigitalInOut(board.EPD_CS)
+epd_dc = digitalio.DigitalInOut(board.EPD_DC)
+epd_reset = digitalio.DigitalInOut(board.EPD_RESET)
+epd_busy =  digitalio.DigitalInOut(board.EPD_BUSY)
+srcs = None
+
+from adafruit_epd.ssd1680 import Adafruit_SSD1680
+display = Adafruit_SSD1680(122, 250, spi, cs_pin=epd_cs, dc_pin=epd_dc,
+                           sramcs_pin=srcs, rst_pin=epd_reset,
+                           busy_pin=epd_busy)
+
+display.rotation = 3
+display.fill(Adafruit_EPD.WHITE)
+
+display.fill_rect(20, 20, 50, 60, Adafruit_EPD.BLACK)
+display.hline(80, 30, 60, Adafruit_EPD.BLACK)
+display.vline(80, 30, 60, Adafruit_EPD.BLACK)
+
+# draw repeatedly with pauses
+while True:
+    display.display()
+    time.sleep(15)

examples/feather_epd_blinka_pillow.py

@@ -0,0 +1,93 @@
+# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+import digitalio
+import busio
+import board
+from adafruit_epd.epd import Adafruit_EPD
+import time
+
+from PIL import Image
+from PIL import ImageDraw
+from PIL import ImageFont
+
+# create the spi device and pins we will need
+spi = busio.SPI(board.EPD_SCK, MOSI=board.EPD_MOSI, MISO=None)
+epd_cs = digitalio.DigitalInOut(board.EPD_CS)
+epd_dc = digitalio.DigitalInOut(board.EPD_DC)
+epd_reset = digitalio.DigitalInOut(board.EPD_RESET)
+epd_busy =  digitalio.DigitalInOut(board.EPD_BUSY)
+srcs = None
+
+from adafruit_epd.ssd1680 import Adafruit_SSD1680
+display = Adafruit_SSD1680(122, 250, spi, cs_pin=epd_cs, dc_pin=epd_dc,
+                           sramcs_pin=srcs, rst_pin=epd_reset,
+                           busy_pin=epd_busy)
+
+display.rotation = 3
+# Create blank image for drawing.
+# Make sure to create image with mode '1' for 1-bit color.
+width = display.width
+height = display.height
+image = Image.new("RGB", (width, height))
+
+WHITE = (0xFF, 0xFF, 0xFF)
+BLACK = (0x00, 0x00, 0x00)
+
+# clear the display
+display.fill(Adafruit_EPD.WHITE)
+
+# Get drawing object to draw on image.
+draw = ImageDraw.Draw(image)
+# empty it
+draw.rectangle((0, 0, width, height), fill=WHITE)
+
+# Draw an outline box
+draw.rectangle((1, 1, width - 2, height - 2), outline=BLACK, fill=WHITE)
+# Draw some shapes.
+# First define some constants to allow easy resizing of shapes.
+padding = 5
+shape_width = 30
+top = padding
+bottom = height - padding
+# Move left to right keeping track of the current x position for drawing shapes.
+x = padding
+# Draw an ellipse.
+draw.ellipse((x, top, x + shape_width, bottom), outline=BLACK, fill=WHITE)
+x += shape_width + padding
+# Draw a rectangle.
+draw.rectangle((x, top, x + shape_width, bottom), outline=WHITE, fill=BLACK)
+x += shape_width + padding
+# Draw a triangle.
+draw.polygon(
+    [(x, bottom), (x + shape_width / 2, top), (x + shape_width, bottom)],
+    outline=BLACK,
+    fill=WHITE,
+)
+x += shape_width + padding
+# Draw an X.
+draw.line((x, bottom, x + shape_width, top), fill=BLACK)
+draw.line((x, top, x + shape_width, bottom), fill=BLACK)
+x += shape_width + padding
+
+# Load default font.
+font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", 20)
+
+# Alternatively load a TTF font.  Make sure the .ttf font
+# file is in the same directory as the python script!
+# Some other nice fonts to try: http://www.dafont.com/bitmap.php
+# font = ImageFont.truetype('Minecraftia.ttf', 8)
+
+# Write two lines of text.
+draw.text((x, top), "Hello", font=font, fill=BLACK)
+draw.text((x, top + 20), "World!", font=font, fill=BLACK)
+
+display.image(image)
+display.display()
+
+time.sleep(10)
+
+blinkaimage = Image.open('examples/epd_bonnet_blinka_250x122.bmp')
+display.image(blinkaimage)
+display.display()
+