Pocket e-reader (e-ink pages)

Three pages of Alice in Wonderland on the 1.54″ e-paper panel. Click the button to turn the page; each turn streams 5000 bytes into the SSD1681 RAM and fires a full refresh, flash and all. The current page survives a power cut, exactly like the paperback it is.

What's on the bench

• Battery
• Button
• E-Ink 1.54″ 200×200
• ESP32-C3
• Resistor

The code

This MicroPython script runs on the emulated board every boot; edit it in the Code tab.

from machine import Pin, SoftSPI
import framebuf, time
spi = SoftSPI(baudrate=2000000, sck=Pin(4), mosi=Pin(5), miso=Pin(0))
cs, dc, rst = Pin(6, Pin.OUT, value=1), Pin(7, Pin.OUT), Pin(3, Pin.OUT, value=1)
busy = Pin(10, Pin.IN)
btn = Pin(1, Pin.IN)
def cmd(c, data=b""):
    cs(0); dc(0); spi.write(bytes([c]))
    if data:
        dc(1); spi.write(data)
    cs(1)
def wait():
    while busy.value():
        time.sleep_ms(20)
rst(0); time.sleep_ms(10); rst(1); time.sleep_ms(10)
cmd(0x12); wait()
W = H = 200
buf = bytearray(W * H // 8)
fb = framebuf.FrameBuffer(buf, W, H, framebuf.MONO_HLSB)
PAGES = [
    ("ALICE IN WONDERLAND", [
        "Alice was beginning",
        "to get very tired of",
        "sitting by her",
        "sister on the bank,",
        "and of having",
        "nothing to do: once",
        "or twice she had",
        "peeped into the book",
        "her sister was",
        "reading, but it had",
        "no pictures in it,",
    ]),
    ("CHAPTER I (cont.)", [
        "'and what is the use",
        "of a book,' thought",
        "Alice, 'without",
        "pictures or",
        "conversations?'",
        "",
        "So she was",
        "considering in her",
        "own mind...",
    ]),
    ("ABOUT THIS READER", [
        "Each page you see",
        "travelled over SPI:",
        "5000 bytes into the",
        "SSD1681 RAM, then",
        "one Master",
        "Activation refresh.",
        "",
        "E-paper keeps its",
        "page with the power",
        "cut - try it.",
    ]),
]
def show(n):
    title, lines = PAGES[n]
    fb.fill(1)
    fb.fill_rect(0, 0, 200, 18, 0)
    fb.text(title, 8, 6, 1)
    y = 30
    for ln in lines:
        fb.text(ln, 8, y, 0)
        y += 14
    fb.text("page %d/%d - button turns" % (n + 1, len(PAGES)), 4, 188, 0)
    cmd(0x11, b'\x03')
    cmd(0x44, bytes([0, W // 8 - 1]))
    cmd(0x45, b'\x00\x00' + bytes([(H - 1) & 0xFF, (H - 1) >> 8]))
    cmd(0x4E, b'\x00'); cmd(0x4F, b'\x00\x00')
    cmd(0x24, buf); cmd(0x22, b'\xF7'); cmd(0x20); wait()
    print("page", n + 1, "shown")
page = 0
show(page)
while True:
    if btn.value():
        page = (page + 1) % len(PAGES)
        show(page)
        while btn.value():
            time.sleep_ms(20)
    time.sleep_ms(30)