Setting up lvgl_micropython on the "Cheap Yellow Board" (CYB) aka Sunton ESP32 2432S028R 2.8" resistive touch LCD board

[gitcnd]

Setting up lvgl_micropython on the "Cheap Yellow Board" (CYB) aka Sunton ESP32 2432S028R 2.8" resistive touch LCD board #281

The "Cheap Yellow Board" is a popular screen. There's 3 versions (see https://github.com/rzeldent/platformio-espressif32-sunton/blob/main/esp32-2432S028R.json for differences). Below is how to set up the original or v2 boards, which use the ili9341 display driver and xpt2046 touch chips (curiously, my board had "7789" on the box, but it is not a st7789 driver.

Below is how I got the screen and touch working on my ESP32 2432S028

Build:-

python3 make.py esp32 BOARD=ESP32_GENERIC BOARD_VARIANT=SPIRAM DISPLAY=ili9341 INDEV=xpt2046

Note: the xpt2046 driver is my modified one with "swapxy" feature added, which it does not work without.

(Optional) backup your flash before overwriting it:

export PORT=/dev/ttyS6 esptool.py --port $PORT read_flash 0x0 0x400000 lcd_2.8inch_ESP32-2432S028R .bin

Flash:-

esptool.py --port $PORT write_flash 0x0 lvgl_micropy_ESP32_GENERIC-SPIRAM-4.bin

Upload a test:-

ampy --port $PORT put lvgl_test_2432S028R.py

Run it:-

mcu_serial.pl -port $PORT
import lvgl_test_2432S028R

The test program:

#WORKS lvgl_test_2432S028R_l.py

import lcd_bus
from micropython import const
import machine



# display settings
_WIDTH = const(320)
_HEIGHT = const(240)
_BL = const(21)
_RST = const(-1)  # ST7789_DEV_CONFIG_RESET_GPIO_NUM=GPIO_NUM_NC
_DC = const(2)  # ST7789_SPI_CONFIG_DC_GPIO_NUM=2

_MOSI = const(13)  # ST7789_SPI_BUS_MOSI_IO_NUM=13
_MISO = const(12)  # ST7789_SPI_BUS_MISO_IO_NUM=12
_SCK = const(14)  # ST7789_SPI_BUS_SCLK_IO_NUM=14
_HOST = const(1)  # SPI2

_LCD_CS = const(15)
# _LCD_FREQ = const(80000000)
_LCD_FREQ = const(24000000)  # ST7789_SPI_CONFIG_PCLK_HZ=24000000

_TOUCH_CS = const(33) 
_TOUCH_FREQ = const(2000000)  # GT911_I2C_CONFIG_MASTER_CLK_SPEED=400000

spi_bus = machine.SPI.Bus(
    host=_HOST,
    mosi=_MOSI,
    miso=_MISO,
    sck=_SCK
)

display_bus = lcd_bus.SPIBus(
    spi_bus=spi_bus,
    freq=_LCD_FREQ,
    dc=_DC,
    cs=_LCD_CS,
)

# we are going to let the display driver sort out the best freame buffer size and where to allocate it to.
# fb1 = display_bus.allocate_framebuffer(_BUFFER_SIZE, lcd_bus.MEMORY_INTERNAL | lcd_bus.MEMORY_DMA)
# fb2 = display_bus.allocate_framebuffer(_BUFFER_SIZE, lcd_bus.MEMORY_INTERNAL | lcd_bus.MEMORY_DMA)

import ili9341  # NOQA
import lvgl as lv  # NOQA


display = ili9341.ILI9341(
    data_bus=display_bus,
    display_width=_WIDTH,
    display_height=_HEIGHT,
    backlight_pin=_BL,
    backlight_on_state=ili9341.STATE_PWM,
    color_space=lv.COLOR_FORMAT.RGB565,
    color_byte_order=ili9341.BYTE_ORDER_RGB,
    rgb565_byte_swap=True
)


import task_handler  # NOQA

import xpt2046  # NOQA

spi0_bus = machine.SPI.Bus(
    host=2,
    mosi=32,
    miso=39,
    sck=25
)

touch_dev = machine.SPI.Device(
    spi_bus=spi0_bus,
    freq=_TOUCH_FREQ,
    cs=_TOUCH_CS
)


display.set_power(True)
display.init(type=1)
#display.set_rotation(lv.DISPLAY_ROTATION._180)
display.set_backlight(100)
indev = xpt2046.XPT2046(touch_dev, swapxy=True ,startup_rotation=2)

# 0     - works nicely, but sideways
# 1     - sketchy - might be _WIDTH/_HEIGHT mixup?
# 2     - works nicely, but sideways
# 3     - sketchy backwards horizontal
# 4

#touch_dev = machine.SPI.Device( spi_bus=spi_bus, freq=_TOUCH_FREQ, cs=_TOUCH_CS)
#cnd    indev = gt911.GT911(touch_dev)  AttributeError: 'Device' object has no attribute 'write_mem'   File "gt911.py", line 50, in _write_reg

th = task_handler.TaskHandler()

scrn = lv.screen_active()
scrn.set_style_bg_color(lv.color_hex(0x000000), 0)

slider = lv.slider(scrn)
slider.set_size(300, 50)
slider.center()

main_label = lv.label(scrn)
main_label.set_text('HELLO WORLD!')
main_label.align(lv.ALIGN.CENTER, 0, -50)

# Create and position the R label
r_label = lv.label(scrn)
r_label.set_text('R')
r_label.set_style_text_color(lv.color_hex(0xFF0000), 0)
r_label.align_to(main_label, lv.ALIGN.OUT_TOP_LEFT, -20, -10)

# Create and position the G label
g_label = lv.label(scrn)
g_label.set_text('G')
g_label.set_style_text_color(lv.color_hex(0x00FF00), 0)
g_label.align_to(main_label, lv.ALIGN.OUT_TOP_MID, 0, -10)

# Create and position the B label
b_label = lv.label(scrn)
b_label.set_text('B')
b_label.set_style_text_color(lv.color_hex(0x0000FF), 0)
b_label.align_to(main_label, lv.ALIGN.OUT_TOP_RIGHT, 20, -10)

Screenshots:-

[kdschlosser]

with the XPT touch you ALWAYS need to run the calibration routine. Do not set the swap_xy parameter and simply initilize the driver then add this code directly below the driver startup..

if not indev.is_calibrated:
    indev.calibrate()

The calibration data is automatically saved into NVS so it is persistent between restarts. If you remove erasing the ESP32 prior to flashing firmware the changes will even be persistent between flashes of new firmware.