# pico_epaper_42_gs.py A 2-bit greyscale display driver for the Waveshare Pico # ePaper 4.2" display. This version fixes bugs and supports partial updates. # https://github.com/peterhinch/micropython-nano-gui/blob/master/drivers/epaper/pico_epaper_42.py # Adapted from the Waveshare driver by Peter Hinch Sept 2022-May 2023. # https://www.waveshare.com/pico-epaper-4.2.htm # UC8176 manual https://www.waveshare.com/w/upload/8/88/UC8176.pdf # Waveshare's original. # https://github.com/waveshare/Pico_ePaper_Code/blob/main/python/Pico-ePaper-4.2.py # ***************************************************************************** # * | File : Pico_ePaper-3.7.py # * | Author : Waveshare team # * | Function : Electronic paper driver # * | Info : # *---------------- # * | This version: V1.0 # * | Date : 2021-06-01 # # | Info : python demo # ----------------------------------------------------------------------------- # Permission is hereby granted, free of charge, to any person obtaining a copy # of this software and associated documnetation 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 # furished 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 OR 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. # If .set_partial() is called, subsequent updates will be partial. To restore normal # updates, issue .set_full() from machine import Pin, SPI import framebuf import time import asyncio from drivers.boolpalette import BoolPalette def asyncio_running(): try: _ = asyncio.current_task() except: return False return True # Display resolution _EPD_WIDTH = const(400) _BWIDTH = _EPD_WIDTH // 4 # FB width in bytes (2 bits/pixel) _EPD_HEIGHT = const(300) _RST_PIN = const(12) _DC_PIN = const(8) _CS_PIN = const(9) _BUSY_PIN = const(13) # ************************************ greyscale LUT************************************** # 0~3 gray EPD_grey_lut_vcom = b"\x00\x0A\x00\x00\x00\x01\x60\x14\x14\x00\x00\x01\x00\x14\x00\x00\x00\x01\ \x00\x13\x0A\x01\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" # R21 EPD_grey_lut_ww = b"\x40\x0A\x00\x00\x00\x01\x90\x14\x14\x00\x00\x01\x10\x14\x0A\x00\x00\ \x01\xA0\x13\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" # R22H r EPD_grey_lut_bw = b"\x40\x0A\x00\x00\x00\x01\x90\x14\x14\x00\x00\x01\x00\x14\x0A\x00\x00\x01\x99\x0C\ \x01\x03\x04\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" # R23H w EPD_grey_lut_wb = b"\x40\x0A\x00\x00\x00\x01\x90\x14\x14\x00\x00\x01\x00\x14\x0A\x00\x00\ \x01\x99\x0B\x04\x04\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" # R24H b EPD_grey_lut_bb = b"\x80\x0A\x00\x00\x00\x01\x90\x14\x14\x00\x00\x01\x20\x14\x0A\x00\x00\ \x01\x50\x13\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" # Framebuf mapping is pixel 0 is in LS 2 bits @micropython.viper def _lmap(dest: ptr8, source: ptr8, pattern: int, length: int): d: int = 0 # dest index s: int = 0 # Source index e: int = 0 # Current output byte (8 pixels of 1 bit t: int = 0 # Current input byte (4 pixels of 2 bits) while d < length: # For each byte of o/p e = 0 # Two sets of 4 pixels for _ in range(2): t = source[s] for _ in range(4): e |= (pattern >> (t & 3)) & 1 t >>= 2 e <<= 1 s += 1 dest[d] = e >> 1 d += 1 # Color mapping. # There is no LUT - colors.py creates 13 color constants which have 2-bit values determined # by EPD.rgb(). These 2-bit values are written to the framebuf. The _lmap function produces # 1-bit colors which are written to two buffers on the hardware. Each buffer is written using # a different LUT so that grey values appear as 1 in one hardware buffer and 0 in the other. class EPD(framebuf.FrameBuffer): # The rgb method maps colors onto a 2-bit greyscale # colors.py creates color constants with 2-bit colors which are written to FB @staticmethod def rgb(r, g, b): return min((r + g + b) >> 7, 3) # Greyscale in range 0 <= gs <= 3 # Discard asyn arg: autodetect def __init__(self, spi=None, cs=None, dc=None, rst=None, busy=None, asyn=False): self._rst = Pin(_RST_PIN, Pin.OUT) if rst is None else rst self._busy_pin = Pin(_BUSY_PIN, Pin.IN, Pin.PULL_UP) if busy is None else busy self._cs = Pin(_CS_PIN, Pin.OUT) if cs is None else cs self._dc = Pin(_DC_PIN, Pin.OUT) if dc is None else dc self._spi = SPI(1, sck=Pin(10), mosi=Pin(11), miso=Pin(28)) if spi is None else spi self._spi.init(baudrate=10_000_000) # Datasheet allows 10MHz self._busy = False # Set immediately on .show(). Cleared when busy pin is logically false (physically 1). # Async API self.updated = asyncio.Event() self.complete = asyncio.Event() # Public bound variables required by nanogui. # Dimensions in pixels as seen by nanogui self.width = _EPD_WIDTH self.height = _EPD_HEIGHT # Other public bound variable. # Special mode enables demos written for generic displays to run. self.demo_mode = False self._buf = bytearray(_EPD_HEIGHT * _BWIDTH) self._mvb = memoryview(self._buf) self.ibuf = bytearray(1000) # Buffer for mapped pixels # Patterns for the two hardware buffers. # LS 4 bits are o/p colors for white, grey1, grey2, black self._patterns = (0b0011, 0b0101) mode = framebuf.GS2_HMSB self.palette = BoolPalette(mode) super().__init__(self._buf, _EPD_WIDTH, _EPD_HEIGHT, mode) self.init() time.sleep_ms(500) # Hardware reset def reset(self): for v in (1, 0, 1): self._rst(v) time.sleep_ms(20) def _command(self, command, data=None): self._dc(0) self._cs(0) self._spi.write(command) self._cs(1) if data is not None: self._data(data) # Datasheet P26 seems to mandate CS False after each byte. Ugh. def _data(self, data, buf1=bytearray(1)): self._dc(1) for b in data: self._cs(0) buf1[0] = b self._spi.write(buf1) self._cs(1) def display_on(self): self._command(b"\x12") time.sleep_ms(100) self.wait_until_ready() def init(self): self.reset() self._command(b"\x01", b"\x03\x00\x2b\x2b\x13") # POWER SETTING # Set "red" pixel voltage to 6.2V self._command(b"\x06", b"\x17\x17\x17") # boost soft start self._command(b"\x04") # POWER_ON self.wait_until_ready() self._command( b"\x00", b"\x3F" ) # panel setting. Works with BF and 3F, not with 1F or 2F. But black border. # KW-BF KWR-AF BWROTP 0f BWOTP 1f PGH was 0xBF self._command(b"\x30", b"\x3C") # PLL setting self._command(b"\x61", b"\x01\x90\x01\x2C") # resolution setting self._command(b"\x82", b"\x12") # vcom_DC setting PGH 0x28 in normal driver self._command( b"\x50", b"\x57" ) # VCOM AND DATA INTERVAL SETTING PGH 97 black border 57 white border self.set_grey() # Greyscale LUT def set_grey(self): self._command(b"\x20", EPD_grey_lut_vcom) self._command(b"\x21", EPD_grey_lut_ww) self._command(b"\x22", EPD_grey_lut_bw) self._command(b"\x23", EPD_grey_lut_wb) self._command(b"\x24", EPD_grey_lut_bb) self._command(b"\x25", EPD_grey_lut_ww) def wait_until_ready(self): while not self.ready(): time.sleep_ms(100) def set_partial(self): # Allow demos to run pass def set_full(self): pass # For polling in asynchronous code. Just checks pin state. # 0 == busy. Comment in official code is wrong. Code is correct. def ready(self): return not (self._busy or (self._busy_pin() == 0)) # 0 == busy @micropython.native def _bsend(self, start, pattern, nbytes): buf = self.ibuf _lmap(buf, self._mvb[start:], pattern, nbytes) # Invert image data for EPD self._dc(1) self._cs(0) self._spi.write(buf) self._cs(1) async def _as_show(self): for idx, pattern in enumerate(self._patterns): self._command(b"\x13" if idx else b"\x10") fbidx = 0 # Index into framebuf nbytes = len(self.ibuf) # Bytes to send didx = nbytes * 2 # Increment of framebuf index nleft = len(self._buf) # Size of framebuf npass = 0 while nleft > 0: self._bsend(fbidx, pattern, nbytes) # Grey-map, buffer and send nbytes fbidx += didx # Adjust for bytes already sent nleft -= didx nbytes = min(nbytes, nleft) if not ((npass := npass + 1) % 16): await asyncio.sleep_ms(0) # Control blocking time self.updated.set() self._command(b"\x12") # Nonblocking .display_on() while not self._busy_pin(): # Wait on display hardware await asyncio.sleep_ms(0) self._busy = False self.complete.set() async def do_refresh(self, split): # For micro-gui assert not self._busy, "Refresh while busy" await self._as_show() # split=5 def show(self): # nanogui if self._busy: raise RuntimeError("Cannot refresh: display is busy.") self._busy = True # Immediate busy flag. Pin goes low much later. if asyncio_running(): self.updated.clear() self.complete.clear() asyncio.create_task(self._as_show()) return for idx, pattern in enumerate(self._patterns): self._command(b"\x13" if idx else b"\x10") fbidx = 0 # Index into framebuf nbytes = len(self.ibuf) # Bytes to send didx = nbytes * 2 # Increment of framebuf index nleft = len(self._buf) # Size of framebuf while nleft > 0: self._bsend(fbidx, pattern, nbytes) # Grey-map, buffer and send nbytes fbidx += didx # Adjust for bytes already sent. nleft -= didx # Could be < 0 if framebuf size not divisible by ibuf size nbytes = min(nbytes, nleft) # but iteration will stop self._busy = False self.display_on() if not self.demo_mode: # Immediate return to avoid blocking the whole application. # User should wait for ready before calling refresh() return self.wait_until_ready() time.sleep_ms(2000) # Give time for user to see result def sleep(self): # self._command(b"\x02") # power off # self.wait_until_ready() self._command(b"\x07", b"\xA5") # deep sleep