Adafruit_CircuitPython_EPD/adafruit_epd/jd79661.py
2025-07-22 17:10:07 -04:00

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Python

# SPDX-FileCopyrightText: 2024
#
# SPDX-License-Identifier: MIT
"""
`adafruit_epd.jd79661` - Adafruit JD79661 - quad-color ePaper display driver
====================================================================================
CircuitPython driver for Adafruit JD79661 quad-color display breakouts
* Author(s): [Your name here]
**Hardware:**
* JD79661 Quad-Color ePaper Display
**Notes on Architecture:**
This is the first quad-color display in the CircuitPython EPD library. Unlike tri-color
displays that use separate buffers for black and red/yellow, the JD79661 uses a single
buffer with 2 bits per pixel to represent 4 colors (black, white, yellow, red).
This driver overrides the parent class's dual-buffer architecture to accommodate the
quad-color packed pixel format. All drawing operations are reimplemented to work with
the 2-bit color depth.
"""
import time
import adafruit_framebuf
from micropython import const
from adafruit_epd.epd import Adafruit_EPD
try:
"""Needed for type annotations"""
import typing
from busio import SPI
from digitalio import DigitalInOut
from typing_extensions import Literal
except ImportError:
pass
__version__ = "0.0.0+auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_EPD.git"
# Command constants
_JD79661_PANEL_SETTING = const(0x00)
_JD79661_POWER_SETTING = const(0x01)
_JD79661_POWER_OFF = const(0x02)
_JD79661_POWER_ON = const(0x04)
_JD79661_BOOSTER_SOFTSTART = const(0x06)
_JD79661_DEEP_SLEEP = const(0x07)
_JD79661_DATA_START_XMIT = const(0x10)
_JD79661_DISPLAY_REFRESH = const(0x12)
_JD79661_PLL_CONTROL = const(0x30)
_JD79661_CDI = const(0x50)
_JD79661_RESOLUTION = const(0x61)
# Color constants for internal use (2-bit values)
_JD79661_BLACK = const(0b00)
_JD79661_WHITE = const(0b01)
_JD79661_YELLOW = const(0b10)
_JD79661_RED = const(0b11)
# Other command constants from init sequence
_JD79661_POFS = const(0x03)
_JD79661_TCON = const(0x60)
_JD79661_CMD_E7 = const(0xE7)
_JD79661_CMD_E3 = const(0xE3)
_JD79661_CMD_B4 = const(0xB4)
_JD79661_CMD_B5 = const(0xB5)
_JD79661_CMD_E9 = const(0xE9)
_JD79661_CMD_4D = const(0x4D)
class Adafruit_JD79661(Adafruit_EPD):
"""driver class for Adafruit JD79661 quad-color ePaper display breakouts
This driver implements a quad-color display with a single buffer using 2 bits
per pixel. This differs from the parent class architecture which assumes
separate buffers for black and color pixels in tri-color displays.
**Color Architecture:**
- Uses a single buffer with 2 bits per pixel
- Supports 4 colors: BLACK (0b00), WHITE (0b01), YELLOW (0b10), RED (0b11)
- All drawing methods are overridden to handle the 2-bit packed pixel format
- The parent class's dual-buffer methods (_blackframebuf/_colorframebuf) are
set to the same buffer for compatibility but are not used directly
"""
# Add color constants for convenience - these match parent class where applicable
BLACK = const(0) # 0b00 in the display buffer
WHITE = const(1) # 0b01 in the display buffer
YELLOW = const(2) # 0b10 in the display buffer
RED = const(3) # 0b11 in the display buffer
def __init__(
self,
width: int,
height: int,
spi: SPI,
*,
cs_pin: DigitalInOut,
dc_pin: DigitalInOut,
sramcs_pin: DigitalInOut,
rst_pin: DigitalInOut,
busy_pin: DigitalInOut,
) -> None:
"""Initialize the quad-color display driver.
Note: This driver uses a different buffer architecture than the parent class.
Instead of separate black and color buffers, it uses a single buffer with
2 bits per pixel to represent 4 colors.
"""
super().__init__(width, height, spi, cs_pin, dc_pin, sramcs_pin, rst_pin, busy_pin)
# Adjust width to be divisible by 8 for proper byte alignment
stride = width
if stride % 8 != 0:
stride += 8 - stride % 8
# For quad-color display, we need 2 bits per pixel
# So buffer size is width * height / 4 bytes
self._buffer1_size = int(stride * height / 4)
self._buffer2_size = 0 # No second buffer for this display
if sramcs_pin:
self._buffer1 = self.sram.get_view(0)
# IMPORTANT: Both buffers point to the same memory for compatibility
# with parent class, but only _buffer1 is actually used
self._buffer2 = self._buffer1
else:
self._buffer1 = bytearray(self._buffer1_size)
# IMPORTANT: Both buffers point to the same memory for compatibility
# with parent class, but only _buffer1 is actually used
self._buffer2 = self._buffer1
# Create framebuffers for API compatibility with parent class
# NOTE: These framebuffers are not used for actual drawing operations
# since they don't support 2-bit color depth. All drawing is done
# through overridden methods that directly manipulate the buffer.
self._framebuf1 = adafruit_framebuf.FrameBuffer(
self._buffer1,
width,
height,
stride=stride,
buf_format=adafruit_framebuf.MHMSB,
)
self._framebuf2 = self._framebuf1 # Same framebuffer for compatibility
# Set single byte transactions
self._single_byte_tx = True
# Set up buffer references for parent class compatibility
# Both point to the same buffer since we don't have separate color planes
self.set_black_buffer(0, False)
self.set_color_buffer(0, False)
# Initialize with default fill
self.fill(Adafruit_JD79661.WHITE)
def begin(self, reset: bool = True) -> None:
"""Begin communication with the display and set basic settings"""
if reset:
self.hardware_reset()
time.sleep(0.1)
self.power_down()
def busy_wait(self) -> None:
"""Wait for display to be done with current task, either by polling the
busy pin, or pausing. Note: JD79661 busy is HIGH when busy"""
if self._busy:
while not self._busy.value: # Wait for busy HIGH
time.sleep(0.01)
else:
time.sleep(0.5)
def power_up(self) -> None:
"""Power up the display in preparation for writing RAM and updating"""
self.hardware_reset()
self.busy_wait()
# Send initialization sequence
time.sleep(0.01) # Wait 10ms
self.command(_JD79661_CMD_4D, bytearray([0x78]))
self.command(_JD79661_PANEL_SETTING, bytearray([0x8F, 0x29])) # PSR, Display resolution is 128x250
self.command(_JD79661_POWER_SETTING, bytearray([0x07, 0x00])) # PWR
self.command(_JD79661_POFS, bytearray([0x10, 0x54, 0x44])) # POFS
self.command(_JD79661_BOOSTER_SOFTSTART, bytearray([0x05, 0x00, 0x3F, 0x0A, 0x25, 0x12, 0x1A]))
self.command(_JD79661_CDI, bytearray([0x37])) # CDI
self.command(_JD79661_TCON, bytearray([0x02, 0x02])) # TCON
self.command(_JD79661_RESOLUTION, bytearray([0, 128, 0, 250])) # TRES
self.command(_JD79661_CMD_E7, bytearray([0x1C]))
self.command(_JD79661_CMD_E3, bytearray([0x22]))
self.command(_JD79661_CMD_B4, bytearray([0xD0]))
self.command(_JD79661_CMD_B5, bytearray([0x03]))
self.command(_JD79661_CMD_E9, bytearray([0x01]))
self.command(_JD79661_PLL_CONTROL, bytearray([0x08]))
self.command(_JD79661_POWER_ON)
self.busy_wait()
def power_down(self) -> None:
"""Power down the display - required when not actively displaying!"""
# Only deep sleep if we have a reset pin
if self._rst:
self.command(_JD79661_POWER_OFF, bytearray([0x00]))
self.busy_wait()
self.command(_JD79661_DEEP_SLEEP, bytearray([0xA5]))
time.sleep(0.1)
def update(self) -> None:
"""Update the display from internal memory"""
self.command(_JD79661_DISPLAY_REFRESH, bytearray([0x00]))
self.busy_wait()
if not self._busy:
time.sleep(1) # Wait 1 second if no busy pin
def write_ram(self, index: Literal[0, 1]) -> int:
"""Send the one byte command for starting the RAM write process.
Note: The index parameter is ignored since JD79661 uses a single buffer.
This parameter exists for API compatibility with the parent class.
"""
# JD79661 uses same command for all data
return self.command(_JD79661_DATA_START_XMIT, end=False)
def set_ram_address(self, x: int, y: int) -> None:
"""Set the RAM address location.
Note: Not used on JD79661 chipset. Exists for API compatibility.
"""
# Not used for JD79661
pass
def fill(self, color: int) -> None:
"""Fill the entire display with the specified color.
This method is overridden to handle the 2-bit packed pixel format
used by the quad-color display.
Args:
color: Color value (BLACK, WHITE, YELLOW, or RED)
Raises:
ValueError: If an invalid color is specified
"""
# Map colors to fill patterns (4 pixels per byte)
color_map = {
Adafruit_JD79661.BLACK: 0x00, # 0b00000000 - all pixels black
Adafruit_JD79661.WHITE: 0x55, # 0b01010101 - all pixels white
Adafruit_JD79661.YELLOW: 0xAA, # 0b10101010 - all pixels yellow
Adafruit_JD79661.RED: 0xFF, # 0b11111111 - all pixels red
}
if color not in color_map:
raise ValueError(f"Invalid color: {color}. Use BLACK (0), WHITE (1), YELLOW (2), or RED (3).")
fill_byte = color_map[color]
if self.sram:
self.sram.erase(0x00, self._buffer1_size, fill_byte)
else:
for i in range(self._buffer1_size):
self._buffer1[i] = fill_byte
def pixel(self, x: int, y: int, color: int) -> None:
"""Draw a single pixel in the display buffer.
This method is overridden to handle the 2-bit packed pixel format.
Each byte contains 4 pixels, with 2 bits per pixel.
Args:
x: X coordinate
y: Y coordinate
color: Color value (BLACK, WHITE, YELLOW, or RED)
"""
if (x < 0) or (x >= self.width) or (y < 0) or (y >= self.height):
return
# Handle rotation
if self.rotation == 1:
x, y = y, x
x = self._width - x - 1
if self._width % 8 != 0:
x -= self._width % 8
elif self.rotation == 2:
x = self._width - x - 1
y = self._height - y - 1
if self._width % 8 != 0:
x += self._width % 8
elif self.rotation == 3:
x, y = y, x
y = self._height - y - 1
# Calculate stride (width adjusted to be divisible by 8)
stride = self._width
if stride % 8 != 0:
stride += 8 - stride % 8
# Map color constants to 2-bit values
color_map = {
Adafruit_JD79661.BLACK: _JD79661_BLACK,
Adafruit_JD79661.WHITE: _JD79661_WHITE,
Adafruit_JD79661.YELLOW: _JD79661_YELLOW,
Adafruit_JD79661.RED: _JD79661_RED,
}
if color not in color_map:
# Default to white for invalid colors
pixel_color = _JD79661_WHITE
else:
pixel_color = color_map[color]
# Calculate byte address (4 pixels per byte)
addr = (x + y * stride) // 4
# Calculate bit offset within byte (2 bits per pixel)
# Pixels are packed left-to-right, MSB first
bit_offset = (3 - (x % 4)) * 2
# Create masks
byte_mask = 0x3 << bit_offset
byte_value = (pixel_color & 0x3) << bit_offset
# Read, modify, write
if self.sram:
current = self.sram.read8(addr)
current &= ~byte_mask
current |= byte_value
self.sram.write8(addr, current)
else:
self._buffer1[addr] &= ~byte_mask
self._buffer1[addr] |= byte_value
# Override these methods to handle quad-color properly
def rect(self, x: int, y: int, width: int, height: int, color: int) -> None:
"""Draw a rectangle.
Overridden to use the quad-color pixel method.
"""
for i in range(x, x + width):
self.pixel(i, y, color)
self.pixel(i, y + height - 1, color)
for j in range(y + 1, y + height - 1):
self.pixel(x, j, color)
self.pixel(x + width - 1, j, color)
def fill_rect(self, x: int, y: int, width: int, height: int, color: int) -> None:
"""Fill a rectangle with the passed color.
Overridden to use the quad-color pixel method.
"""
for i in range(x, x + width):
for j in range(y, y + height):
self.pixel(i, j, color)
def line(self, x_0: int, y_0: int, x_1: int, y_1: int, color: int) -> None:
"""Draw a line from (x_0, y_0) to (x_1, y_1) in passed color.
Overridden to use the quad-color pixel method.
"""
# Bresenham's line algorithm
dx = abs(x_1 - x_0)
dy = abs(y_1 - y_0)
sx = 1 if x_0 < x_1 else -1
sy = 1 if y_0 < y_1 else -1
err = dx - dy
while True:
self.pixel(x_0, y_0, color)
if x_0 == x_1 and y_0 == y_1:
break
e2 = 2 * err
if e2 > -dy:
err -= dy
x_0 += sx
if e2 < dx:
err += dx
y_0 += sy
def text(
self,
string: str,
x: int,
y: int,
color: int,
*,
font_name: str = "font5x8.bin",
size: int = 1,
) -> None:
"""Write text string at location (x, y) in given color, using font file.
This method is for CircuitPython's built-in bitmap fonts only.
For TrueType fonts, use PIL/Pillow to draw text on an image and then
display the image using the image() method.
"""
# Validate color
if color not in [Adafruit_JD79661.BLACK, Adafruit_JD79661.WHITE,
Adafruit_JD79661.YELLOW, Adafruit_JD79661.RED]:
raise ValueError(f"Invalid color: {color}. Use BLACK (0), WHITE (1), YELLOW (2), or RED (3).")
# Since we can't use the parent's framebuffer text method directly
# (it only supports 1-bit depth), we need to render to a temporary buffer
# and then copy the pixels in the requested color
# Estimate text dimensions
text_width = len(string) * 6 * size # ~6 pixels per char
text_height = 8 * size # 8 pixel high font
# Bounds check
text_width = min(text_width, self.width - x)
text_height = min(text_height, self.height - y)
if text_width <= 0 or text_height <= 0:
return
# Create temporary monochrome buffer
temp_buf_width = ((text_width + 7) // 8) * 8
temp_buf = bytearray((temp_buf_width * text_height) // 8)
# Create temporary framebuffer
temp_fb = adafruit_framebuf.FrameBuffer(
temp_buf,
temp_buf_width,
text_height,
buf_format=adafruit_framebuf.MHMSB
)
# Render text
temp_fb.fill(0)
temp_fb.text(string, 0, 0, 1, font_name=font_name, size=size)
# Copy pixels in the requested color
for j in range(text_height):
for i in range(text_width):
byte_index = (j * temp_buf_width + i) // 8
bit_index = 7 - ((j * temp_buf_width + i) % 8)
if byte_index < len(temp_buf):
if (temp_buf[byte_index] >> bit_index) & 1:
self.pixel(x + i, y + j, color)
def image(self, image: Image) -> None:
"""Set buffer to value of Python Imaging Library image. The image should
be in RGB mode and a size equal to the display size.
"""
imwidth, imheight = image.size
if imwidth != self.width or imheight != self.height:
raise ValueError(
f"Image must be same dimensions as display ({self.width}x{self.height})."
)
if self.sram:
raise RuntimeError("PIL image is not for use with SRAM assist")
# Grab all the pixels from the image, faster than getpixel.
pix = image.load()
# clear out any display buffers
self.fill(Adafruit_EPD.WHITE)
if image.mode == "RGB": # RGB Mode
for y in range(image.size[1]):
for x in range(image.size[0]):
pixel = pix[x, y]
# Check for yellow first (high red + green, low blue)
if (pixel[0] >= 0x80) and (pixel[1] >= 0x80) and (pixel[2] < 0x80):
# yellowish
self.pixel(x, y, Adafruit_JD79661.YELLOW)
# Then check for red (high red, low green and blue)
elif (pixel[0] >= 0x80) and (pixel[1] < 0x80) and (pixel[2] < 0x80):
# reddish
self.pixel(x, y, Adafruit_JD79661.RED)
# Then black (all low)
elif (pixel[0] < 0x80) and (pixel[1] < 0x80) and (pixel[2] < 0x80):
# dark
self.pixel(x, y, Adafruit_JD79661.BLACK)
# else: remains white (from fill)
elif image.mode == "L": # Grayscale
for y in range(image.size[1]):
for x in range(image.size[0]):
pixel = pix[x, y]
if pixel < 0x40: # 0-63
self.pixel(x, y, Adafruit_JD79661.BLACK)
elif pixel < 0x80: # 64-127
self.pixel(x, y, Adafruit_JD79661.YELLOW)
elif pixel < 0xC0: # 128-191
self.pixel(x, y, Adafruit_JD79661.RED)
# else: 192-255 remains white
else:
raise ValueError("Image must be in mode RGB or mode L.")
def image_dithered(self, image, dither_type="floyd-steinberg") -> None:
"""Display an image with dithering to better represent colors/shades.
This method converts the image to use only the 4 available colors
using error diffusion dithering for better visual quality.
Args:
image: PIL Image object
dither_type: Type of dithering - "floyd-steinberg" or "simple"
Raises:
ValueError: If image dimensions don't match display
RuntimeError: If SRAM is being used (not supported)
"""
imwidth, imheight = image.size
if imwidth != self.width or imheight != self.height:
raise ValueError(
f"Image must be same dimensions as display ({self.width}x{self.height})."
)
if self.sram:
raise RuntimeError("PIL image dithering is not supported with SRAM assist")
# Convert to RGB if not already
if image.mode != "RGB":
image = image.convert("RGB")
# Define our 4 color palette in RGB
palette = [
(0, 0, 0), # BLACK
(255, 255, 255), # WHITE
(255, 255, 0), # YELLOW
(255, 0, 0), # RED
]
# Create a working copy of the image as a list of lists
pixels = []
for y in range(imheight):
row = []
for x in range(imwidth):
r, g, b = image.getpixel((x, y))
row.append([r, g, b])
pixels.append(row)
if dither_type == "floyd-steinberg":
# Floyd-Steinberg dithering
for y in range(imheight):
for x in range(imwidth):
old_pixel = pixels[y][x]
# Find closest color in palette
min_dist = float('inf')
closest_color = 0
closest_rgb = palette[0]
for i, pal_color in enumerate(palette):
dist = sum((old_pixel[j] - pal_color[j])**2 for j in range(3))
if dist < min_dist:
min_dist = dist
closest_color = i
closest_rgb = pal_color
# Set pixel to closest color
self.pixel(x, y, closest_color)
# Calculate error
error = [old_pixel[i] - closest_rgb[i] for i in range(3)]
# Distribute error to neighboring pixels
if x + 1 < imwidth:
for i in range(3):
pixels[y][x + 1][i] += error[i] * 7 / 16
if y + 1 < imheight:
if x > 0:
for i in range(3):
pixels[y + 1][x - 1][i] += error[i] * 3 / 16
for i in range(3):
pixels[y + 1][x][i] += error[i] * 5 / 16
if x + 1 < imwidth:
for i in range(3):
pixels[y + 1][x + 1][i] += error[i] * 1 / 16
else: # Simple nearest-color mapping
for y in range(imheight):
for x in range(imwidth):
pixel = pixels[y][x]
# Find closest color in palette
min_dist = float('inf')
closest_color = 0
for i, pal_color in enumerate(palette):
dist = sum((pixel[j] - pal_color[j])**2 for j in range(3))
if dist < min_dist:
min_dist = dist
closest_color = i
self.pixel(x, y, closest_color)
# Parent class drawing method overrides for documentation
def set_black_buffer(self, index: Literal[0, 1], inverted: bool) -> None:
"""Set the index for the black buffer data.
Note: This method exists for API compatibility but has no effect on the
JD79661 since it uses a single buffer with 2-bit color depth rather than
separate black/color buffers.
"""
super().set_black_buffer(index, inverted)
def set_color_buffer(self, index: Literal[0, 1], inverted: bool) -> None:
"""Set the index for the color buffer data.
Note: This method exists for API compatibility but has no effect on the
JD79661 since it uses a single buffer with 2-bit color depth rather than
separate black/color buffers.
"""
super().set_color_buffer(index, inverted)