Add experimental RGB565 SSD1351 driver.

drivers/ssd1351_16bit.py

@@ -0,0 +1,120 @@
+# SSD1351_16bit.py MicroPython driver for Adafruit color OLED displays.
+
+# Adafruit 1.5" 128*128 OLED display: https://www.adafruit.com/product/1431
+# Adafruit 1.27" 128*96 display https://www.adafruit.com/product/1673
+# For wiring details see drivers/ADAFRUIT.md in this repo.
+
+# This driver is based on the Adafruit C++ library for Arduino
+# https://github.com/adafruit/Adafruit-SSD1351-library.git
+
+# The MIT License (MIT)
+
+# Copyright (c) 2018 Peter Hinch
+
+# 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.
+
+import framebuf
+import utime
+import gc
+import micropython
+from uctypes import addressof
+
+# Initialisation commands in cmd_init:
+# 0xfd, 0x12, 0xfd, 0xb1,  # Unlock command mode
+# 0xae,  # display off (sleep mode)
+# 0xb3, 0xf1,  # clock div
+# 0xca, 0x7f,  # mux ratio
+# 0xa0, 0x74,  # setremap 0x74
+# 0x15, 0, 0x7f,  # setcolumn
+# 0x75, 0, 0x7f,  # setrow
+# 0xa1, 0,  # set display start line
+# 0xa2, 0,  # displayoffset
+# 0xb5, 0,  # setgpio
+# 0xab, 1,  # functionselect: serial interface, internal Vdd regulator
+# 0xb1, 0x32,  # Precharge
+# 0xbe, 0x05,  # vcommh
+# 0xa6,  # normaldisplay
+# 0xc1, 0xc8, 0x80, 0xc8,  # contrast abc
+# 0xc7, 0x0f,  # Master contrast
+# 0xb4, 0xa0, 0xb5, 0x55,  # set vsl (see datasheet re ext circuit)
+# 0xb6, 1,  # Precharge 2
+# 0xaf,  # Display on
+
+# SPI baudrate: Pyboard can produce 10.5MHz or 21MHz. Datasheet gives max of 20MHz.
+# Attempt to use 21MHz failed but might work on a PCB or with very short leads.
+class SSD1351(framebuf.FrameBuffer):
+    # Convert r, g, b in range 0-255 to a 16 bit colour value RGB565
+    #  acceptable to hardware: rrrrrggggggbbbbb
+    @staticmethod
+    def rgb(r, g, b):
+        return ((r & 0xf8) << 5) | ((g & 0x1c) << 11) | (b & 0xf8) | ((g & 0xe0) >> 5)
+
+    def __init__(self, spi, pincs, pindc, pinrs, height=128, width=128):
+        if height not in (96, 128):
+            raise ValueError('Unsupported height {}'.format(height))
+        self.spi = spi
+        self.rate = 11000000  # See baudrate note above.
+        self.pincs = pincs
+        self.pindc = pindc  # 1 = data 0 = cmd
+        self.height = height  # Required by Writer class
+        self.width = width
+        # Save color mode for use by writer_gui (blit)
+        self.mode = framebuf.RGB565
+        gc.collect()
+        self.buffer = bytearray(self.height * self.width * 2)
+        super().__init__(self.buffer, self.width, self.height, self.mode)
+        self.mvb = memoryview(self.buffer)
+        pinrs(0)  # Pulse the reset line
+        utime.sleep_ms(1)
+        pinrs(1)
+        utime.sleep_ms(1)
+        # See above comment to explain this allocation-saving gibberish.
+        self._write(b'\xfd\x12\xfd\xb1\xae\xb3\xf1\xca\x7f\xa0\x74'\
+        b'\x15\x00\x7f\x75\x00\x7f\xa1\x00\xa2\x00\xb5\x00\xab\x01'\
+        b'\xb1\x32\xbe\x05\xa6\xc1\xc8\x80\xc8\xc7\x0f'\
+        b'\xb4\xa0\xb5\x55\xb6\x01\xaf', 0)
+        self.show()
+        gc.collect()
+
+    def _write(self, mv, dc):
+        self.spi.init(baudrate=self.rate, polarity=1, phase=1)
+        self.pincs(1)
+        self.pindc(dc)
+        self.pincs(0)
+        self.spi.write(bytes(mv))
+        self.pincs(1)
+
+    # Write lines from the framebuf out of order to match the mapping of the
+    # SSD1351 RAM to the OLED device.
+    def show(self):
+        mvb = self.mvb 
+        bw = self.width * 2  # Width in bytes
+        self._write(b'\x5c', 0)  # Enable data write
+        if self.height == 128:
+            for l in range(128):
+                l0 = (95 - l) % 128  # 95 94 .. 1 0 127 126 .. 96
+                start = l0 * self.width * 2
+                self._write(mvb[start : start + bw], 1)  # Send a line
+        else:
+            for l in range(128):
+                if l < 96:
+                    start = (63 -l) * self.width * 2  # 63 62 .. 1 0
+                else:
+                    start = (191 - l) * self.width * 2  # 127 126 .. 95
+                self._write(mvb[start : start + bw], 1)  # Send a line