Guition JC3248W535 3.5-inch Touchscreen Tablet

Overview

The Guition JC3248W535 combines a 320 × 480 pixel, 3.5-inch IPS TFT with an ESP32-S3-WROOM-1.

Discussed here is the capacitive-touch JC3248W535C_I_Y. There are also versions with resistive touch, and with no touch.

Benefits

• Affordable
• Lots of memory (512 KB SRAM, 16 MB flash, 8 MB PSRAM)
• Enclosure
• QWIIC connector for I²C
• 1S-LiIon/LiPo battery support plus charger
• Capacitive touch
• SD Card Reader
• Speaker (I²S)

Specifications

Interfaces

GPIOs are accessible through three JST 1.25mm and one QWIIC 1.0mm connector on the back of the housing:

P1: Power and UART

4-pin JST 1.25 connector, located right next to the USB-C connector. Provides access to the unregulated input voltage and can be used to power the tablet externally.

P2: Peripherals

8-pin JST 1.25 connector. Provides GPIOs only, main peripheral bus.

P3 and P4: I²C

Available both through a 4-pin JST 1.25 and a 1.0mm QWIIC connector. Pins include regulated 3.3V and GND, perfectly suited for I²C bus.

P5: Battery

Connects to an optional 1S LiIon/LiPo battery. Always make sure to connect the battery in correct polarity. Polarity is marked on the PCB. - is further away relative to the USB-C connector, + is closer located to the USB-C connector.

Power and Battery

The board can be powered in a number of ways:

• USB-C:
  Powers the board and charges an attached LiIon/LiPo 1S battery.
• 5V External:
  P1 +5V passes through the input MOSFET/protection network to the 5 V rail; no wider input range is established.
• Battery:
  When a 1S LiIon/LiPo battery is attached to the BATTERY (P5) connector, and no other power supply is present, the board is powered from the battery.

The battery circuit connects P5 to an unspecified charger/power-management IC, most likely a IP5306.

P6: Speaker

Connects to a speaker.

This is a differential speaker output: neither lead is GND. The I²S signals are GPIO41/DIN, GPIO42/BCLK, and GPIO2/LRCLK.

Both AX98357A and NS4168 datasheets are supplied, but U4 has no part number in the drawing. Identify the actual fitted amplifier before relying on a speaker impedance or output-power rating.

GPIOs

As is the case with many tablet microcontrollers, only limited GPIOs are exposed:

GPIO restrictions and internal pins

• GPIO 5 is connected through R25 (0 Ω) to a battery divider and used for obtaining the battery voltage (i.e. to show a state-of-charge gauge): R26 **33 kΩ** above and R27 100 kΩ below. It is not an isolated general-purpose output.

  With the divider fitted and unloaded, battery_V = adc_pin_V × (33 + 100) / 100 = adc_pin_V × 1.33. This ratio comes from the drawing; it is not ADC calibration. Check populated resistors, ADC attenuation, and calibrated input voltage before implementing measurement.

• GPIO 46 is a strapping pin: external wiring must preserve the required reset/download state.

The exact Arduino-ESP32 3.2.1 generic ESP32-S3 variant defines TX/RX as 43/44, SDA/SCL as 8/9, and SS/MOSI/SCK/MISO as 10/11/12/13. The UART and SD names coincide with the hardware.

The I²C defaults do not match touch, and default SPI does not drive the QSPI display. Use explicit pins as the included BSP does.

Schematics

Page 1

Shows P1 power/UART, USB-C, and the regulator producing 3.3 V.

D1 links the internal 5 V rail and USB VBUS as drawn.

The expansion block shows P2/P3/P4, shared GPIO 17/18, the GPIO 5 battery divider, and the GPIO 3` interrupt link.

The TF block shows a 3.3 V SD socket with pull-ups and SPI signals.

Page 2

Shows the ESP32-S3 module, BOOT to GPIO 0, and RESET on EN/RST.

The LCD connector exposes QSPI, touch, TE, and backlight.

GPIO 1 drives Q2 to switch the LED cathode return: HIGH enables the backlight.

The lower-left block is battery charging/power management with its KEY switch; the lower-right block feeds I²S into U4 and filters its speaker outputs. The “resistive touch”/“capacitive touch” section headings are misplaced: use nets and components to identify those blocks.

Programming

PlatformIO: LVGL color and touch test

Open examples/lvgl-test in PlatformIO.

The complete project includes the supplied vendor display initialization, touch driver, LVGL port, and configuration. No third-party driver with a placeholder repository address is required.

The pinned pioarduino platform provides Arduino-ESP32 3.2.1 / ESP-IDF 5.4, matching the IDF 5 interfaces used by this vendor driver. Standard PlatformIO espressif32 with Arduino 2.x is not a drop-in substitute. LVGL 8.4.0 matches the supplied library; do not substitute LVGL 9.

platformio.ini

[env:jc3248w535]
platform = https://github.com/pioarduino/platform-espressif32/releases/download/54.03.21/platform-espressif32.zip
board = esp32-s3-devkitc-1
framework = arduino
board_build.arduino.memory_type = qio_opi
board_build.flash_mode = qio
board_build.f_flash = 80000000L
board_upload.flash_size = 16MB
board_upload.maximum_size = 16777216
board_build.partitions = default_16MB.csv
monitor_speed = 115200
build_flags =
    -DBOARD_HAS_PSRAM
    -DARDUINO_USB_MODE=1
    -DARDUINO_USB_CDC_ON_BOOT=1
    -DLV_CONF_INCLUDE_SIMPLE
    -Isrc
lib_deps = lvgl/[email protected]

The generic board is a build target, with tablet-specific 16 MB flash and octal PSRAM overrides. The supplied Arduino settings selected only 8 MB flash despite the manufacturer’s 16 MB specification; this configuration follows the specification. Verify actual flash size if your unit differs.

The included src/lv_conf.h sets LV_COLOR_DEPTH = 16 and LV_COLOR_16_SWAP = 1. The vendor driver expects this byte order; do not swap pixels again in the application. The full 320 × 480 × 2 = 307,200 byte RGB565 buffer resides in PSRAM, with DMA transport buffers in internal RAM. BSP buffer sizes are pixels; SPI transfer sizes are bytes.

src/main.cpp

#include <Arduino.h>
#include <lvgl.h>
#include "display.h"
#include "esp_bsp.h"

static lv_obj_t *status_label;
static const char *names[] = {"RED", "GREEN", "BLUE"};
static const uint32_t rgb[] = {0xFF0000, 0x00FF00, 0x0000FF};
static uint32_t touches = 0;

static void on_press(lv_event_t *event) {
    const uintptr_t index = (uintptr_t)lv_event_get_user_data(event);
    lv_point_t point_px = {0, 0};
    lv_indev_t *input = lv_indev_get_act();
    if (input) lv_indev_get_point(input, &point_px);
    lv_label_set_text_fmt(status_label, "%s #%lu  x=%d y=%d",
        names[index], (unsigned long)++touches, point_px.x, point_px.y);
    Serial.printf("%s: x_px=%d y_px=%d\n", names[index], point_px.x, point_px.y);
}

void setup() {
    Serial.begin(115200);
    if (!psramFound()) {
        Serial.println("Octal PSRAM missing: check board configuration");
        while (true) delay(1000);
    }
    bsp_display_cfg_t cfg = {};
    cfg.lvgl_port_cfg = ESP_LVGL_PORT_INIT_CONFIG();
    cfg.buffer_size = 320 * 480; // pixels; RGB565 uses 307200 bytes
    cfg.rotate = LV_DISP_ROT_NONE; // portrait: x=0..319, y=0..479
    if (!bsp_display_start_with_config(&cfg)) {
        Serial.println("Display/touch initialization failed");
        while (true) delay(1000);
    }
    ESP_ERROR_CHECK(bsp_display_backlight_on());
    if (!bsp_display_lock(0)) return; // 0 = wait indefinitely, milliseconds otherwise
    lv_obj_t *screen = lv_scr_act();
    lv_obj_set_style_bg_color(screen, lv_color_hex(0x000000), 0);
    lv_obj_clear_flag(screen, LV_OBJ_FLAG_SCROLLABLE);
    for (uintptr_t i = 0; i < 3; ++i) {
        lv_obj_t *button = lv_btn_create(screen);
        lv_obj_set_pos(button, 10, 10 + i * 130);
        lv_obj_set_size(button, 300, 120);
        lv_obj_set_style_bg_color(button, lv_color_hex(rgb[i]), LV_PART_MAIN);
        lv_obj_set_style_bg_opa(button, LV_OPA_COVER, LV_PART_MAIN);
        lv_obj_set_style_radius(button, 0, LV_PART_MAIN);
        lv_obj_add_event_cb(button, on_press, LV_EVENT_PRESSED, (void *)i);
        lv_obj_t *label = lv_label_create(button);
        lv_label_set_text(label, names[i]);
        lv_obj_set_style_text_color(label, lv_color_hex(i == 1 ? 0x000000 : 0xFFFFFF), 0);
        lv_obj_center(label);
    }
    status_label = lv_label_create(screen);
    lv_label_set_text(status_label, "Touch RED, GREEN, BLUE");
    lv_obj_set_style_text_color(status_label, lv_color_hex(0xFFFFFF), 0);
    lv_obj_align(status_label, LV_ALIGN_BOTTOM_MID, 0, -25);
    bsp_display_unlock();
}

void loop() {
    delay(20); // vendor port supplies the LVGL task and millisecond tick
}

Keep the accompanying .c and .h files in src/: main.cpp is the UI, not a complete panel-driver replacement. Built-in demo widgets are disabled. The vendor port supplies the LVGL task and millisecond tick; do not call a second lv_timer_handler() or lv_tick_inc() from loop().

The tested Python build environment uses PlatformIO Core 6.2.0 and Click 8.1.8. The pinned platform’s esptool 5.0.0-dev1 fails with newer Click API signatures, so keep this environment separate from ESPHome. Create it on Windows with:

py -m venv .venv
.\.venv\Scripts\python.exe -m pip install -r requirements-build.txt
.\.venv\Scripts\python.exe -m platformio run
.\.venv\Scripts\python.exe -m platformio run --target upload
.\.venv\Scripts\python.exe -m platformio device monitor --baud 115200

When using an already compatible PlatformIO environment, the equivalent commands are:

pio run
pio run --target upload
pio device monitor --baud 115200

Expected result: labeled RED, GREEN, BLUE bands from top to bottom. Each press updates its color name, count, and pixel position on-screen and over USB. Portrait x increases rightward from 0 to 319; y increases downward from 0 to 479. Test all four corners, then release/repress each button to check input mapping and release behavior. This exercises one pointer, not multi-touch.

Red/blue reversal points to RGB/BGR order. Broad color corruption suggests RGB565 byte order. Touch selecting another region suggests an axis/rotation mismatch. A lit blank panel calls for checking initialization/QSPI; a dark panel also requires checking power and GPIO1/backlight.

ESPHome: Color and Touch Diagnostic

jc3248w535.yaml is a complete USB-only diagnostic: no Wi-Fi secrets or Home Assistant required. It draws RGB bands and reports the touched band and coordinates in the USB log. The JC4832W535 preset intentionally follows the official example with this panel’s pin mapping; it does not rename the hardware.

Target ESPHome 2026.9.1. Its official documentation marks qspi_dbi for eventual removal in favor of mipi_spi, but the former still supplies this documented board preset. Pin the version; migration needs its own model/initialization check.

See also here for a working example.

# ESPHome 2026.9.1; USB-only color/touch diagnostic, no Wi-Fi secrets required.
esphome:
  name: jc3248w535-test

esp32:
  board: esp32-s3-devkitc-1
  variant: esp32s3
  flash_size: 16MB
  framework:
    type: esp-idf

logger:
  hardware_uart: USB_SERIAL_JTAG

psram:
  mode: octal
  speed: 80MHz

spi:
  id: display_qspi
  type: quad
  clk_pin: GPIO47
  data_pins: [GPIO21, GPIO48, GPIO40, GPIO39]

i2c:
  id: touch_i2c
  sda: GPIO4
  scl: GPIO8
  frequency: 400kHz
  scan: true

power_supply:
  - id: backlight
    pin: GPIO1
    enable_on_boot: true

display:
  - platform: qspi_dbi
    id: lcd
    model: JC4832W535
    spi_id: display_qspi
    data_rate: 40MHz
    cs_pin:
      number: GPIO45
      ignore_strapping_warning: true
    dimensions:
      width: 320
      height: 480
    rotation: 0
    color_order: rgb
    invert_colors: false
    update_interval: 250ms
    lambda: |-
      it.filled_rectangle(0, 0, 320, 160, Color(255, 0, 0));
      it.filled_rectangle(0, 160, 320, 160, Color(0, 255, 0));
      it.filled_rectangle(0, 320, 320, 160, Color(0, 0, 255));

touchscreen:
  - platform: axs15231
    id: panel_touch
    display: lcd
    i2c_id: touch_i2c
    update_interval: 50ms
    on_touch:
      - lambda: |-
          const int x_px = touch.x;
          const int y_px = touch.y;
          const char *band = y_px < 160 ? "RED" : (y_px < 320 ? "GREEN" : "BLUE");
          ESP_LOGI("touch", "%s: x_px=%d y_px=%d raw=(%d,%d)",
                   band, x_px, y_px, touch.x_raw, touch.y_raw);

esphome config jc3248w535.yaml
esphome compile jc3248w535.yaml
esphome run jc3248w535.yaml --device COM7

Replace COM7 with the device port. Touch the top/middle/bottom bands: logs should report RED/GREEN/BLUE at that position. No transform is applied in portrait. Landscape needs a corresponding touch transform; ESPHome’s 270-degree board example swaps XY and mirrors Y. Confirm every corner after changing orientation.

For later Home Assistant use, add Wi-Fi with your own secrets, api:, and the current ota: platform configuration. The initial test has no network dependencies.

Factory Recovery

Use a USB data cable and select the ESP32-S3’s enumerated USB port. The schematic connects USB directly to the MCU; the supplied CH340 archive does not establish a need for a CH340 driver. If upload cannot connect, hold BOOT, press/release RESET, release BOOT, and select the download port. Reset after flashing if necessary.

The factory image is E TOOLS/Burn files/JC3248W535C_I_Y_EN-80M.bin. The supplied screenshots select ESP32-S3 / Develop / USB, then a combined image at 0x0, QIO, 80 MHz. That address applies to the corresponding combined factory image, not arbitrary application binaries. Back up factory contents if you need to preserve them. The download tool’s old dl_temp binaries are not recovery images for this board by default.

Materials

• 15231_0626.zip
• AX98357AETE T_2021-01-06.PDF
• AXS15231_Datasheet_V0.5_20230306.pdf
• esp32-s3-wroom-1_wroom-1u_datasheet_en.pdf
• esp32-s3_datasheet_en.pdf
• JC3248W535 Specifications-EN.pdf
• Nsiway-NS4168.pdf

Original demos, utilities, and factory firmware remain in the source collection. The inventory accounts for them without reproducing build caches or historical logs.

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