141 lines
4.9 KiB
Python
141 lines
4.9 KiB
Python
#!/usr/bin/env python
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# Substantially derived from code by (c) 2015 Richard Hull The MIT License (MIT)
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# https://github.com/rm-hull/ssd1306:
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# "Permission is hereby granted, free of charge, to any person obtaining a copy
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# "of this software and associated documentation files (the "Software"), to deal
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# "in the Software without restriction, including without limitation the rights
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# "to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# "copies of the Software, and to permit persons to whom the Software is
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# "furnished to do so, subject to the following conditions:
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# "The above copyright notice and this permission notice shall be included in
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# "all copies or substantial portions of the Software."
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#
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# B Lavery 2015:
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# This derivative "library" module is not installed to the python system as Hull's version was:
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# it simply resides alongside your own python script.
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# In this version, the I2C bus object needs to be handed in as a parameter from your user code.
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# This makes this one same library file work with either Raspberry Pi or Virtual GPIO system.
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# Hull's (clever) auto-displaying "canvas" is replaced by a persistent draw object
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# which can be incrementally changed. This canvas needs coded "display()" calls to push to the hardware.
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from PIL import Image, ImageDraw
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class ssd1306():
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def __init__(self, bus, address=0x3C):
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self.cmd_mode = 0x00
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self.data_mode = 0x40
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self.bus = bus
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self.addr = address
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self.width = 128
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self.height = 64
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self.pages = int(self.height / 8)
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self.image = Image.new('1', (self.width, self.height))
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self.canvas = ImageDraw.Draw(self.image) # this is a "draw" object for preparing display contents
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self._command(
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const.DISPLAYOFF,
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const.SETDISPLAYCLOCKDIV, 0x80,
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const.SETMULTIPLEX, 0x3F,
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const.SETDISPLAYOFFSET, 0x00,
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const.SETSTARTLINE,
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const.CHARGEPUMP, 0x14,
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const.MEMORYMODE, 0x00,
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const.SEGREMAP,
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const.COMSCANDEC,
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const.SETCOMPINS, 0x12,
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const.SETCONTRAST, 0xCF,
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const.SETPRECHARGE, 0xF1,
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const.SETVCOMDETECT, 0x40,
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const.DISPLAYALLON_RESUME,
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const.NORMALDISPLAY,
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const.DISPLAYON)
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def _command(self, *cmd):
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"""
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Sends a command or sequence of commands through to the
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device - maximum allowed is 32 bytes in one go.
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LIMIT ON ARDUINO: CMD BYTE + 31 = 32, SO LIMIT TO 31 bl
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"""
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assert(len(cmd) <= 31)
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self.bus.write_i2c_block_data(self.addr, self.cmd_mode, list(cmd))
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def _data(self, data):
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"""
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Sends a data byte or sequence of data bytes through to the
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device - maximum allowed in one transaction is 32 bytes, so if
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data is larger than this it is sent in chunks.
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In our library, only data operation used is 128x64 long, ie whole canvas.
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"""
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for i in range(0, len(data), 31):
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self.bus.write_i2c_block_data(self.addr, self.data_mode, list(data[i:i+31]))
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def display(self):
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"""
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The image on the "canvas" is flushed through to the hardware display.
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Takes the 1-bit image and dumps it to the SSD1306 OLED display.
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"""
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self._command(
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const.COLUMNADDR, 0x00, self.width-1, # Column start/end address
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const.PAGEADDR, 0x00, self.pages-1) # Page start/end address
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pix = list(self.image.getdata())
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step = self.width * 8
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buf = []
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for y in range(0, self.pages * step, step):
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i = y + self.width-1
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while i >= y:
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byte = 0
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for n in range(0, step, self.width):
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byte |= (pix[i + n] & 0x01) << 8
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byte >>= 1
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buf.append(byte)
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i -= 1
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self._data(buf) # push out the whole lot
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def cls(self):
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self.canvas.rectangle((0, 0, self.width-1, self.height-1), outline=0, fill=0)
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self.display()
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def onoff(self, onoff):
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if onoff == 0:
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self._command(const.DISPLAYOFF)
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else:
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self._command(const.DISPLAYON)
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class const:
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CHARGEPUMP = 0x8D
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COLUMNADDR = 0x21
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COMSCANDEC = 0xC8
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COMSCANINC = 0xC0
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DISPLAYALLON = 0xA5
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DISPLAYALLON_RESUME = 0xA4
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DISPLAYOFF = 0xAE
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DISPLAYON = 0xAF
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EXTERNALVCC = 0x1
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INVERTDISPLAY = 0xA7
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MEMORYMODE = 0x20
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NORMALDISPLAY = 0xA6
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PAGEADDR = 0x22
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SEGREMAP = 0xA0
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SETCOMPINS = 0xDA
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SETCONTRAST = 0x81
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SETDISPLAYCLOCKDIV = 0xD5
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SETDISPLAYOFFSET = 0xD3
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SETHIGHCOLUMN = 0x10
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SETLOWCOLUMN = 0x00
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SETMULTIPLEX = 0xA8
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SETPRECHARGE = 0xD9
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SETSEGMENTREMAP = 0xA1
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SETSTARTLINE = 0x40
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SETVCOMDETECT = 0xDB
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SWITCHCAPVCC = 0x2
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