# pico_epaper_42.py A 1-bit monochrome 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 copy of this driver. # https://github.com/waveshare/Pico_ePaper_Code/blob/main/pythonNanoGui/drivers/ePaper4in2.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 uasyncio as 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 // 8 _EPD_HEIGHT = const(300) _RST_PIN = const(12) # Rear socket pinout _DC_PIN = const(8) _CS_PIN = const(9) _BUSY_PIN = const(13) # LUT elements vcom, ww, bw, wb, bb # ****************************** full screen update LUT********************************* # lut_full = (b"\x00\x08\x08\x00\x00\x02\x00\x0F\x0F\x00\x00\x01\x00\x08\x08\x00\ \x00\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00\x00\x00", b"\x50\x08\x08\x00\x00\x02\x90\x0F\x0F\x00\x00\x01\xA0\x08\x08\x00\x00\x02\ \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", b"\x50\x08\x08\x00\x00\x02\x90\x0F\x0F\x00\x00\x01\xA0\x08\x08\x00\x00\x02\ \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", b"\xA0\x08\x08\x00\x00\x02\x90\x0F\x0F\x00\x00\x01\x50\x08\x08\x00\x00\x02\ \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", b"\x20\x08\x08\x00\x00\x02\x90\x0F\x0F\x00\x00\x01\x10\x08\x08\x00\x00\x02\ \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", ) # ******************************partial screen update LUT********************************* # lut_part = ( b"\x00\x19\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00\x00\x00", b"\x00\x19\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00", b"\x80\x19\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00", b"\x40\x19\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00", b"\x00\x19\x01\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ \x00\x00\x00\x00", ) # [index into LUT, register address]. Design allows for repeats as per greyscale driver. lut_map = ((0, b"\x20"), (1, b"\x21"), (2, b"\x22"), (3, b"\x23"), (4, b"\x24")) # Invert: EPD is black on white # 337/141 us for 2000 bytes (125/250MHz) @micropython.viper def _linv(dest: ptr32, source: ptr32, length: int): n: int = length - 1 z: uint32 = int(0xFFFFFFFF) while n >= 0: dest[n] = source[n] ^ z n -= 1 class EPD(framebuf.FrameBuffer): # A monochrome approach should be used for coding this. The rgb method ensures # nothing breaks if users specify colors. @staticmethod def rgb(r, g, b): return int((r > 127) or (g > 127) or (b > 127)) # Discard asyn: 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 limit 10MHz # Busy flag: set immediately on .show(). Cleared when busy pin is logically false. self._busy = False # 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 inverted pixels mode = framebuf.MONO_HLSB self.palette = BoolPalette(mode) # Enable CWriter. 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() cmd = self._command cmd(b"\x01", b"\x03\x00\x2b\x2b") # Booster soft start. Matches datasheet. cmd(b"\x06", b"\x17\x17\x17") cmd(b"\x04") # Power on self.wait_until_ready() cmd(b"\x00", b"\xbf") # panel setting cmd(b"\x30", b"\x3c") # PLL setting cmd(b"\x61", b"\x01\x90\x01\x2C") # resolution setting cmd(b"\x82", b"\x28") # vcom_DC setting cmd(b"\x50", b"\x97") # VCOM AND DATA INTERVAL SETTING # 97white border 77black border VBDF 17|D7 VBDW 97 VBDB 57 VBDF F7 VBDW 77 VBDB 37 VBDR B7 self.set_full() def send_lut(self, lm, lut): for idx, reg in lm: self._command(reg, lut[idx]) def set_full(self): # Normal full updates self.send_lut(lut_map, lut_full) def set_partial(self): # Partial updates self.send_lut(lut_map, lut_part) def wait_until_ready(self): while not self.ready(): time.sleep_ms(100) # 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, nbytes): # Invert b<->w, buffer and send nbytes source bytes buf = self._ibuf # Invert and buffer is done 32 bits at a time, hence >> 2 _linv(buf, self._mvb[start:], nbytes >> 2) self._dc(1) self._cs(0) self._spi.write(buf) self._cs(1) # Time to convert and transmit 1000 bytes ~ 1ms: most of that is tx @ 10MHz # Yield every 16 transfers means blocking is ~16ms # Total convert and transmit time for 15000 bytes is ~15ms. # Timing @10MHz/250MHz: full refresh 2.1s, partial 740ms: the bulk of the time # is spent spinning on the busy pin and is CPU frequency independent. async def _as_show(self): self._command(b"\x13") fbidx = 0 # Index into framebuf nbytes = len(self._ibuf) # Bytes to send nleft = len(self._buf) # Size of framebuf npass = 0 while nleft > 0: self._bsend(fbidx, nbytes) # Invert, buffer and send nbytes fbidx += nbytes # Adjust for bytes already sent nleft -= nbytes 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() # Specific method for micro-gui. Unsuitable EPD's lack this method. Micro-gui # does not test for asyncio as this is guaranteed to be up. async def do_refresh(self, split): 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 self._command(b"\x13") fbidx = 0 # Index into framebuf nbytes = len(self._ibuf) # Bytes to send nleft = len(self._buf) # Size of framebuf while nleft > 0: self._bsend(fbidx, nbytes) # Invert, buffer and send nbytes fbidx += nbytes # Adjust for bytes already sent nleft -= nbytes nbytes = min(nbytes, nleft) 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) # Demo mode: 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