st7789.py

"""
Copyright (c) 2020, 2021 Russ Hughes

This file incorporates work covered by the following copyright and
permission notice and is licensed under the same terms:

The MIT License (MIT)

Copyright (c) 2019 Ivan Belokobylskiy

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation 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
furnished 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 FOR 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.

The driver is based on devbis' st7789py_mpy module from
https://github.com/devbis/st7789py_mpy.

This driver adds support for:

- 320x240, 240x240 and 135x240 pixel displays
- Display rotation
- Hardware based scrolling
- Drawing text using 8 and 16 bit wide bitmap fonts with heights that are
  multiples of 8.  Included are 12 bitmap fonts derived from classic pc
  BIOS text mode fonts.
- Drawing text using converted TrueType fonts.
- Drawing converted bitmaps

"""

import time
from micropython import const
import ustruct as struct

# commands
ST7789_NOP = const(0x00)
ST7789_SWRESET = const(0x01)
ST7789_RDDID = const(0x04)
ST7789_RDDST = const(0x09)

ST7789_SLPIN = const(0x10)
ST7789_SLPOUT = const(0x11)
ST7789_PTLON = const(0x12)
ST7789_NORON = const(0x13)

ST7789_INVOFF = const(0x20)
ST7789_INVON = const(0x21)
ST7789_DISPOFF = const(0x28)
ST7789_DISPON = const(0x29)
ST7789_CASET = const(0x2A)
ST7789_RASET = const(0x2B)
ST7789_RAMWR = const(0x2C)
ST7789_RAMRD = const(0x2E)

ST7789_PTLAR = const(0x30)
ST7789_VSCRDEF = const(0x33)
ST7789_COLMOD = const(0x3A)
ST7789_MADCTL = const(0x36)
ST7789_VSCSAD = const(0x37)

ST7789_MADCTL_MY = const(0x80)
ST7789_MADCTL_MX = const(0x40)
ST7789_MADCTL_MV = const(0x20)
ST7789_MADCTL_ML = const(0x10)
ST7789_MADCTL_BGR = const(0x08)
ST7789_MADCTL_MH = const(0x04)
ST7789_MADCTL_RGB = const(0x00)

ST7789_RDID1 = const(0xDA)
ST7789_RDID2 = const(0xDB)
ST7789_RDID3 = const(0xDC)
ST7789_RDID4 = const(0xDD)

COLOR_MODE_65K = const(0x50)
COLOR_MODE_262K = const(0x60)
COLOR_MODE_12BIT = const(0x03)
COLOR_MODE_16BIT = const(0x05)
COLOR_MODE_18BIT = const(0x06)
COLOR_MODE_16M = const(0x07)

# Color definitions
BLACK = const(0x0000)
BLUE = const(0x001F)
RED = const(0xF800)
GREEN = const(0x07E0)
CYAN = const(0x07FF)
MAGENTA = const(0xF81F)
YELLOW = const(0xFFE0)
WHITE = const(0xFFFF)

_ENCODE_PIXEL = ">H"
_ENCODE_POS = ">HH"
_DECODE_PIXEL = ">BBB"

_BUFFER_SIZE = const(256)

_BIT7 = const(0x80)
_BIT6 = const(0x40)
_BIT5 = const(0x20)
_BIT4 = const(0x10)
_BIT3 = const(0x08)
_BIT2 = const(0x04)
_BIT1 = const(0x02)
_BIT0 = const(0x01)

# Rotation tables (width, height, xstart, ystart)[rotation % 4]

WIDTH_320 = [(240, 320,  0,  0),
             (320, 240,  0,  0),
             (240, 320,  0,  0),
             (320, 240,  0,  0)]

WIDTH_240 = [(240, 240,  0,  0),
             (240, 240,  0,  0),
             (240, 240,  0, 80),
             (240, 240, 80,  0)]

WIDTH_135 = [(135, 240, 52, 40),
             (240, 135, 40, 53),
             (135, 240, 53, 40),
             (240, 135, 40, 52)]

# MADCTL ROTATIONS[rotation % 4]
ROTATIONS = [0x00, 0x60, 0xc0, 0xa0]


def color565(red, green=0, blue=0):
    """
    Convert red, green and blue values (0-255) into a 16-bit 565 encoding.
    """
    try:
        red, green, blue = red  # see if the first var is a tuple/list
    except TypeError:
        pass
    return (red & 0xf8) << 8 | (green & 0xfc) << 3 | blue >> 3


def _encode_pos(x, y):
    """Encode a postion into bytes."""
    return struct.pack(_ENCODE_POS, x, y)


def _encode_pixel(color):
    """Encode a pixel color into bytes."""
    return struct.pack(_ENCODE_PIXEL, color)


class ST7789():
    """
    ST7789 driver class

    Args:
        spi (spi): spi object **Required**
        width (int): display width **Required**
        height (int): display height **Required**
        reset (pin): reset pin
        dc (pin): dc pin **Required**
        cs (pin): cs pin
        backlight(pin): backlight pin
        rotation (int): display rotation
            - 0-Portrait
            - 1-Landscape
            - 2-Inverted Portrait
            - 3-Inverted Landscape
    """
    def __init__(self, spi, width, height, reset=None, dc=None,
                 cs=None, backlight=None, rotation=0):
        """
        Initialize display.
        """
        if height != 240 or width not in [320, 240, 135]:
            raise ValueError(
                "Unsupported display. 320x240, 240x240 and 135x240 are supported."
            )

        if dc is None:
            raise ValueError("dc pin is required.")

        self._display_width = self.width = width
        self._display_height = self.height = height
        self.xstart = 0
        self.ystart = 0
        self.spi = spi
        self.reset = reset
        self.dc = dc
        self.cs = cs
        self.backlight = backlight
        self._rotation = rotation % 4

        self.hard_reset()
        self.soft_reset()
        self.sleep_mode(False)

        self._set_color_mode(COLOR_MODE_65K | COLOR_MODE_16BIT)
        time.sleep_ms(50)
        self.rotation(self._rotation)
        self.inversion_mode(True)
        time.sleep_ms(10)
        self._write(ST7789_NORON)
        time.sleep_ms(10)
        if backlight is not None:
            backlight.value(1)
        self._write(ST7789_DISPON)
        time.sleep_ms(500)

    def _write(self, command=None, data=None):
        """SPI write to the device: commands and data."""
        if self.cs:
            self.cs.off()

        if command is not None:
            self.dc.off()
            self.spi.write(bytes([command]))
        if data is not None:
            self.dc.on()
            self.spi.write(data)
            if self.cs:
                self.cs.on()

    def hard_reset(self):
        """
        Hard reset display.
        """
        if self.cs:
            self.cs.off()
        if self.reset:
            self.reset.on()
        time.sleep_ms(50)
        if self.reset:
            self.reset.off()
        time.sleep_ms(50)
        if self.reset:
            self.reset.on()
        time.sleep_ms(150)
        if self.cs:
            self.cs.on()

    def soft_reset(self):
        """
        Soft reset display.
        """
        self._write(ST7789_SWRESET)
        time.sleep_ms(150)

    def sleep_mode(self, value):
        """
        Enable or disable display sleep mode.

        Args:
            value (bool): if True enable sleep mode. if False disable sleep
            mode
        """
        if value:
            self._write(ST7789_SLPIN)
        else:
            self._write(ST7789_SLPOUT)

    def inversion_mode(self, value):
        """
        Enable or disable display inversion mode.

        Args:
            value (bool): if True enable inversion mode. if False disable
            inversion mode
        """
        if value:
            self._write(ST7789_INVON)
        else:
            self._write(ST7789_INVOFF)

    def _set_color_mode(self, mode):
        """
        Set display color mode.

        Args:
            mode (int): color mode
                COLOR_MODE_65K, COLOR_MODE_262K, COLOR_MODE_12BIT,
                COLOR_MODE_16BIT, COLOR_MODE_18BIT, COLOR_MODE_16M
        """
        self._write(ST7789_COLMOD, bytes([mode & 0x77]))

    def rotation(self, rotation):
        """
        Set display rotation.

        Args:
            rotation (int):
                - 0-Portrait
                - 1-Landscape
                - 2-Inverted Portrait
                - 3-Inverted Landscape
        """

        rotation %= 4
        self._rotation = rotation
        madctl = ROTATIONS[rotation]

        if self._display_width == 320:
            table = WIDTH_320
        elif self._display_width == 240:
            table = WIDTH_240
        elif self._display_width == 135:
            table = WIDTH_135
        else:
            raise ValueError(
                "Unsupported display. 320x240, 240x240 and 135x240 are supported."
            )

        self.width, self.height, self.xstart, self.ystart = table[rotation]
        self._write(ST7789_MADCTL, bytes([madctl]))

    def _set_columns(self, start, end):
        """
        Send CASET (column address set) command to display.

        Args:
            start (int): column start address
            end (int): column end address
        """
        if start <= end <= self.width:
            self._write(ST7789_CASET, _encode_pos(
                start+self.xstart, end + self.xstart))

    def _set_rows(self, start, end):
        """
        Send RASET (row address set) command to display.

        Args:
            start (int): row start address
            end (int): row end address
       """
        if start <= end <= self.height:
            self._write(ST7789_RASET, _encode_pos(
                start+self.ystart, end+self.ystart))

    def _set_window(self, x0, y0, x1, y1):
        """
        Set window to column and row address.

        Args:
            x0 (int): column start address
            y0 (int): row start address
            x1 (int): column end address
            y1 (int): row end address
        """
        self._set_columns(x0, x1)
        self._set_rows(y0, y1)
        self._write(ST7789_RAMWR)


    def blit_buffer(self, buffer, x, y, width, height):
        """
        Copy buffer to display at the given location.

        Args:
            buffer (bytes): Data to copy to display
            x (int): Top left corner x coordinate
            Y (int): Top left corner y coordinate
            width (int): Width
            height (int): Height
        """
        self._set_window(x, y, x + width - 1, y + height - 1)
        self._write(None, buffer)