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Waveshare ESP32-S3-Touch-LCD-4 (without "B"), Rev 4.0: working override for the 4B profile

sebastianrakSuggested this wish · —

Summary

The ESP32-S3-Touch-LCD-4 without "B" (PCB revision V4.0) runs Tessera with an Override YAML on top of the Waveshare 4B profile. Glass and grid are the same as the 4B (480 x 480, 2 x 3); only the hardware differs. The full override is in the configuration field.

Hardware (rev V4.0)

From Waveshare's BSP esp32_s3_touch_lcd_4 and the V4.0 schematic:

I2C: SDA GPIO15, SCL GPIO7, shared by the GT911, the CH32V003 expander (0x24) and the PCF85063 RTC
ST7701S: RGB pins as in ESPHome's WAVESHARE-4-480X480 model; panel setup over SPI with CS GPIO42, SCL GPIO2, SDA GPIO1
CH32V003 lines: EXIO1 TP_RST, EXIO2 TP_INT, EXIO3 LCD_RST, EXIO5 SYS_EN, EXIO6 buzzer, EXIO7 RTC_INT; backlight = the expander's PWM (inverted)
Log over the chip's native USB; UART0 (GPIO43/44) goes to the RS485 transceiver

Findings

ESPHome's CH32V003 driver starts every line as an output, high. That releases the touch and LCD resets, but also switches the buzzer on until EXIO6 is driven low.
With reset_pin on the expander, ESPHome's GT911 driver resets the chip and probes it 56 ms later. On this board that failed every time, with and without interrupt_pin on EXIO2. Waveshare's own BSP waits 200 ms after the reset and then probes 0x5D, then 0x14.
What works: no reset or interrupt pin, setup_priority: 500 for ts_touch (after the display's setup of more than 150 ms), and TP_INT released to an input after boot. The override does that last step through BOOT_BOARD_SETTINGS, which is a workaround; a board file would do it its own way.
Backlight: ESPHome's safe PWM levels (1..247), as on the 7B, so 0 % is very dim rather than dark.

Status

Picture, touch, tiles and Home Assistant work. Not tested yet: the brightness range, standby and wake over hours, several cold starts. I have the board and can test a proper profile.

Hardware testing

We often do not have this board ourselves. Community testing helps establish what actually works. A successful report is evidence for the maintainer to review, not an automatic compatibility claim.

Board details & configuration

Model: Waveshare ESP32-S3-Touch-LCD-4 (not the 4B), PCB revision V4.0, CH32V003 IO expander at 0x24
Chip, RAM and flash: ESP32-S3 (rev 0.2), 8 MB octal PSRAM, 16 MB flash
Display and touch: 4" 480x480 IPS, ST7701S over 16-bit RGB (ESPHome model WAVESHARE-4-480X480, panel setup over SPI on GPIO42/2/1); GT911 touch on I2C (SDA GPIO15, SCL GPIO7); backlight via CH32V003 PWM
Already tried: 1) The Waveshare 4B profile as-is (Tessera app 0.4.90, firmware 0.57.0): boots and joins Home Assistant, backlight on, picture black. The 4B expects a TCA9554 and other pins. 2) The 4B profile plus the Override YAML below: picture, touch, tiles and Home Assistant work. Touch took two more tries: with ESPHome's GT911 reset_pin on EXIO1 (with or without interrupt_pin on EXIO2) the GT911 never answered ("touchscreen is marked FAILED: Calibration error"). Without reset and interrupt pins, and with the touchscreen set up after the display, it has been found every time so far. Not tested yet: brightness range, standby and wake over hours, several cold starts, long-term stability. Built by Tessera with ESPHome 2026.9.0; the configuration also validates on 2026.10.1.
Configuration status: working

Product details

View shared configuration

# Tessera Override YAML: Waveshare ESP32-S3-Touch-LCD-4 (WITHOUT "B"), board revision V4.0
# Built on top of the Waveshare 4B profile (packages/waveshare4b.yaml), app 0.4.90, firmware 0.57.0.
# Sources: Waveshare BSP esp32_s3_touch_lcd_4, ESPHome model WAVESHARE-4-480X480,
# github.com/PedanticAvenger/Waveshare_ESP32-S3-TOUCH-LCD-4 (rev 4.0) and the V4.0 schematic.

# Native USB for the log (this board has no USB-UART chip; UART0 goes to the RS485 transceiver)
logger:
  hardware_uart: USB_SERIAL_JTAG

# I2C: GT911, CH32V003 expander and RTC on GPIO15/GPIO7
i2c:
  id: touch_bus
  sda: GPIO15
  scl: GPIO7

# IO expander: CH32V003 at 0x24 instead of the 4B's TCA9554
pca9554: !remove

waveshare_io_ch32v003:
  - id: expander
    i2c_id: touch_bus

# Panel setup over plain GPIOs (CS GPIO42 comes from the display model)
spi:
  id: lcd
  interface: any
  clk_pin: GPIO2
  mosi_pin: GPIO1

output:
  # Remove the 4B parts: backlight on GPIO4 and the parked setup lines on the TCA9554
  - id: !remove gpio_backlight_pwm
  - id: !remove lcd_select_idle
  - id: !remove lcd_data_idle
  - id: !remove lcd_clock_idle
  # Backlight: CH32V003 PWM, inverted (low = bright); ESPHome's default safe levels (1..247)
  - platform: waveshare_io_ch32v003
    id: gpio_backlight_pwm
    waveshare_io_ch32v003_id: expander
    inverted: true
    safe_pwm_levels:
      min_value: 1
      max_value: 247

switch:
  # EXIO5 = SYS_EN: Waveshare's BSP drives it high at start
  - platform: gpio
    id: board_sys_enable
    internal: true
    restore_mode: ALWAYS_ON
    pin:
      waveshare_io_ch32v003: expander
      number: 5
      mode:
        output: true
  # EXIO6 = buzzer enable: the expander starts with every line high, so keep it off
  - platform: gpio
    id: board_buzzer
    internal: true
    restore_mode: ALWAYS_OFF
    pin:
      waveshare_io_ch32v003: expander
      number: 6
      mode:
        output: true

# The 4B dims an analog input (gamma 1.0); the CH32V003 PWM takes ESPHome's default gamma
light:
  - id: !extend back_light
    gamma_correct: 2.8

# Touch: GT911 (schematic V4.0: TP_RST on EXIO1, TP_INT on EXIO2).
# No reset_pin/interrupt_pin: with them, ESPHome's GT911 driver resets the chip through the expander and
# probes it 56 ms later, which failed here every time ("Calibration error"). Without them the expander's
# start (every line high) releases the reset, the display setup takes >150 ms, and only then the driver
# probes 0x5D / 0x14. setup_priority 500 = after the display (600), before LVGL (400).
touchscreen:
  - id: !extend ts_touch
    setup_priority: 500

substitutions:
  # After boot, release TP_INT (input) so the expander does not drive against the GT911
  BOOT_BOARD_SETTINGS: |-
    id(expander)->pin_mode(2, gpio::FLAG_INPUT);

# Display: ST7701S 480x480 over RGB, reset on EXIO3
display:
  - id: !remove my_display
  - platform: mipi_rgb
    model: WAVESHARE-4-480X480
    id: my_display
    spi_id: lcd
    reset_pin:
      waveshare_io_ch32v003: expander
      number: 3
      mode:
        output: true
    update_interval: never
    auto_clear_enabled: false
    # Init sequence from Waveshare's BSP (esp32_s3_touch_lcd_4.c), as in the rev 4.0 community config
    init_sequence:
      - [0x11, 0x00]
      - [0xFF, 0x77, 0x01, 0x00, 0x00, 0x10]
      - [0xC0, 0x3B, 0x00]
      - [0xC1, 0x0D, 0x02]
      - [0xC2, 0x21, 0x08]
      - [0xCD, 0x08]
      - [0xB0, 0x00, 0x11, 0x18, 0x0E, 0x11, 0x06, 0x07, 0x08, 0x07, 0x22, 0x04, 0x12, 0x0F, 0xAA, 0x31, 0x18]
      - [0xB1, 0x00, 0x11, 0x19, 0x0E, 0x12, 0x07, 0x08, 0x08, 0x08, 0x22, 0x04, 0x11, 0x11, 0xA9, 0x32, 0x18]
      - [0xFF, 0x77, 0x01, 0x00, 0x00, 0x11]
      - [0xB0, 0x60]
      - [0xB1, 0x30]
      - [0xB2, 0x87]
      - [0xB3, 0x80]
      - [0xB5, 0x49]
      - [0xB7, 0x85]
      - [0xB8, 0x21]
      - [0xC1, 0x78]
      - [0xC2, 0x78]
      - delay 20ms
      - [0xE0, 0x00, 0x1B, 0x02]
      - [0xE1, 0x08, 0xA0, 0x00, 0x00, 0x07, 0xA0, 0x00, 0x00, 0x00, 0x44, 0x44]
      - [0xE2, 0x11, 0x11, 0x44, 0x44, 0xED, 0xA0, 0x00, 0x00, 0xEC, 0xA0, 0x00, 0x00]
      - [0xE3, 0x00, 0x00, 0x11, 0x11]
      - [0xE4, 0x44, 0x44]
      - [0xE5, 0x0A, 0xE9, 0xD8, 0xA0, 0x0C, 0xEB, 0xD8, 0xA0, 0x0E, 0xED, 0xD8, 0xA0, 0x10, 0xEF, 0xD8, 0xA0]
      - [0xE6, 0x00, 0x00, 0x11, 0x11]
      - [0xE7, 0x44, 0x44]
      - [0xE8, 0x09, 0xE8, 0xD8, 0xA0, 0x0B, 0xEA, 0xD8, 0xA0, 0x0D, 0xEC, 0xD8, 0xA0, 0x0F, 0xEE, 0xD8, 0xA0]
      - [0xEB, 0x02, 0x00, 0xE4, 0xE4, 0x88, 0x00, 0x40]
      - [0xEC, 0x3C, 0x00]
      - [0xED, 0xAB, 0x89, 0x76, 0x54, 0x02, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x20, 0x45, 0x67, 0x98, 0xBA]
      - [0xFF, 0x77, 0x01, 0x00, 0x00, 0x00]