MicroPythonOS · ThomasFarstrike · Sep 3, 2026 · Aug 29, 2026 · Aug 30, 2026 · Aug 30, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -2,6 +2,8 @@ Future release (next version)
 =====
 
 Board Support:
+- Waveshare ESP32-S3-Touch-LCD-3.5: ES8311 audio support (speaker output + microphone input over I2S, DAC volume default tuned by ear on hardware)
+- Add Waveshare ESP32-S3-Touch-LCD-3.5 (3.5" 320x480 ST7796 over SPI with LCD reset/CS on a PCA9554 IO expander, FT6336 touch, QMI8658 IMU, AXP2101 battery management); vendors the st7796 display driver and adds a PCA9554 expander driver
 - UNIHIKER K10: improve two-button navigation, correct camera preview orientation, and restore button input after camera operations
 - unix/macOS/web: compiler fallback to bytecode on architectures without a native emitter (e.g. macOS on Apple Silicon) instead of runtime-loaded apps using @micropython.native/@micropython.viper failing to import with SyntaxError 'invalid micropython decorator'
 

diff --git a/internal_filesystem/lib/drivers/display/st7796/__init__.py b/internal_filesystem/lib/drivers/display/st7796/__init__.py
@@ -0,0 +1,26 @@
+import sys
+from . import st7796
+from . import _st7796_init
+
+# Register _st7796_init in sys.modules so __import__('_st7796_init') can find it
+# This is needed because display_driver_framework.py uses __import__('_st7796_init')
+# expecting a top-level module, but _st7796_init is in the st7796 package subdirectory
+sys.modules['_st7796_init'] = _st7796_init
+
+# Explicitly define __all__ and re-export public symbols from st7796 module
+__all__ = [
+    'ST7796',
+    'STATE_HIGH',
+    'STATE_LOW',
+    'STATE_PWM',
+    'BYTE_ORDER_RGB',
+    'BYTE_ORDER_BGR',
+]
+
+# Re-export the public symbols
+ST7796 = st7796.ST7796
+STATE_HIGH = st7796.STATE_HIGH
+STATE_LOW = st7796.STATE_LOW
+STATE_PWM = st7796.STATE_PWM
+BYTE_ORDER_RGB = st7796.BYTE_ORDER_RGB
+BYTE_ORDER_BGR = st7796.BYTE_ORDER_BGR
diff --git a/internal_filesystem/lib/drivers/display/st7796/_st7796_init.py b/internal_filesystem/lib/drivers/display/st7796/_st7796_init.py
@@ -0,0 +1,129 @@
+# Copyright (c) 2024 - 2025 Kevin G. Schlosser
+
+import time
+from micropython import const  # NOQA
+
+import lvgl as lv  # NOQA
+
+_SWRESET = const(0x01)
+_SLPOUT = const(0x11)
+_CSCON = const(0xF0)
+_MADCTL = const(0x36)
+_COLMOD = const(0x3A)
+_DIC = const(0xB4)
+_DFC = const(0xB6)
+_DOCA = const(0xE8)
+_PWR2 = const(0xC1)
+_PWR3 = const(0xC2)
+_VCMPCTL = const(0xC5)
+_PGC = const(0xE0)
+_NGC = const(0xE1)
+_INVON = const(0x21)
+_DISPON = const(0x29)
+
+_EM = const(0xB7)
+
+
+def init(self):
+    param_buf = bytearray(14)
+    param_mv = memoryview(param_buf)
+
+    self.set_params(_SWRESET)
+
+    time.sleep_ms(120)  # NOQA
+
+    self.set_params(_SLPOUT)
+
+    time.sleep_ms(120)  # NOQA
+
+    param_buf[0] = 0xC3
+    self.set_params(_CSCON, param_mv[:1])
+
+    param_buf[0] = 0x96
+    self.set_params(_CSCON, param_mv[:1])
+
+    param_buf[0] = (
+        self._madctl(
+            self._color_byte_order,
+            self._ORIENTATION_TABLE  # NOQA
+        )
+    )
+    self.set_params(_MADCTL, param_mv[:1])
+
+    color_size = lv.color_format_get_size(self._color_space)
+    if color_size == 2:  # NOQA
+        pixel_format = 0x05
+    elif color_size == 3:
+        pixel_format = 0x07
+    else:
+        raise RuntimeError(
+            'ST7796 IC only supports '
+            'lv.COLOR_FORMAT.RGB565 or lv.COLOR_FORMAT.RGB888'
+        )
+
+    param_buf[0] = pixel_format
+    self.set_params(_COLMOD, param_mv[:1])
+
+    param_buf[0] = 0xC6
+    self.set_params(_EM, param_mv[:1])
+
+    param_buf[0] = 0x01
+    self.set_params(_DIC, param_mv[:1])
+
+    param_buf[0] = 0x80
+    param_buf[1] = 0x02
+    param_buf[2] = 0x3B
+    self.set_params(_DFC, param_mv[:3])
+
+    param_buf[:8] = bytearray(
+        [
+            0x40, 0x8A, 0x00, 0x00, 0x29, 0x19, 0xA5, 0x33
+        ]
+    )
+    self._data_bus.tx_param(_DOCA, param_mv[:8])
+
+    param_buf[0] = 0x06
+    self.set_params(_PWR2, param_mv[:1])
+
+    param_buf[0] = 0xA7
+    self.set_params(_PWR3, param_mv[:1])
+
+    param_buf[0] = 0x18
+    self.set_params(_VCMPCTL, param_mv[:1])
+
+    time.sleep_ms(120)  # NOQA
+
+    param_buf[:14] = bytearray(
+        [
+            0xF0, 0x09, 0x0b, 0x06, 0x04, 0x15, 0x2F,
+            0x54, 0x42, 0x3C, 0x17, 0x14, 0x18, 0x1B
+        ]
+    )
+    self.set_params(_PGC, param_mv[:14])
+
+    param_buf[:14] = bytearray(
+        [
+            0xF0, 0x09, 0x0B, 0x06, 0x04, 0x03, 0x2D,
+            0x43, 0x42, 0x3B, 0x16, 0x14, 0x17, 0x1B
+        ]
+    )
+    self.set_params(_NGC, param_mv[:14])
+
+    time.sleep_ms(120)  # NOQA
+
+    param_buf[0] = 0x3C
+    self.set_params(_CSCON, param_mv[:1])
+
+    param_buf[0] = 0x69
+    self.set_params(_CSCON, param_mv[:1])
+
+    time.sleep_ms(120)  # NOQA
+
+    # IPS panels are normally-inverted: without INVON the whole display
+    # renders in negative (verified on the Waveshare ESP32-S3-Touch-LCD-3.5).
+    # The st7789 driver does the same for the same reason.
+    self.set_params(_INVON)
+
+    self.set_params(_DISPON)
+
+    time.sleep_ms(120)  # NOQA
diff --git a/internal_filesystem/lib/drivers/display/st7796/st7796.py b/internal_filesystem/lib/drivers/display/st7796/st7796.py
@@ -0,0 +1,26 @@
+# Copyright (c) 2024 - 2025 Kevin G. Schlosser
+
+from micropython import const  # NOQA
+import display_driver_framework
+
+
+STATE_HIGH = display_driver_framework.STATE_HIGH
+STATE_LOW = display_driver_framework.STATE_LOW
+STATE_PWM = display_driver_framework.STATE_PWM
+
+BYTE_ORDER_RGB = display_driver_framework.BYTE_ORDER_RGB
+BYTE_ORDER_BGR = display_driver_framework.BYTE_ORDER_BGR
+
+_MADCTL_MV = const(0x20)
+_MADCTL_MX = const(0x40)
+_MADCTL_MY = const(0x80)
+
+
+class ST7796(display_driver_framework.DisplayDriver):
+
+    _ORIENTATION_TABLE = (
+        _MADCTL_MX,
+        _MADCTL_MV | _MADCTL_MY | _MADCTL_MX,
+        _MADCTL_MY,
+        _MADCTL_MV
+    )
diff --git a/internal_filesystem/lib/drivers/io_expander/pca9554.py b/internal_filesystem/lib/drivers/io_expander/pca9554.py
@@ -0,0 +1,44 @@
+import i2c
+from micropython import const
+
+
+class PCA9554:
+    """PCA9554 / TCA9554 8-bit I2C IO expansion chip.
+
+    Same register layout across the PCA9554/TCA9554/PCA9554A family:
+    input port, output port, polarity inversion, configuration.
+    Used e.g. on the Waveshare ESP32-S3-Touch-LCD-3.5, where the LCD
+    reset and chip-select lines are wired to expander pins EXIO1/EXIO2.
+    """
+
+    REG_INPUT = const(0x00)
+    REG_OUTPUT = const(0x01)
+    REG_POLARITY = const(0x02)
+    REG_CONFIG = const(0x03)
+
+    def __init__(self, i2c_bus: i2c.I2C.Bus, dev_id: int):
+        self.dev = i2c.I2C.Device(bus=i2c_bus, dev_id=dev_id, reg_bits=8)
+        self.directions = 0xFF     # all inputs by default (chip reset state)
+        self.output_states = 0x00
+
+    def _write_reg(self, reg, value):
+        self.dev.write_mem(reg, bytes([value & 0xFF]))
+
+    def _read_reg(self, reg):
+        buf = bytearray(1)
+        self.dev.read_mem(reg, buf=buf)
+        return buf[0]
+
+    def set_output(self, pin, value):
+        """Configure pin (0-7) as output and drive it high (True) or low."""
+        if value:
+            self.output_states |= (1 << pin)
+        else:
+            self.output_states &= ~(1 << pin)
+        self._write_reg(self.REG_OUTPUT, self.output_states)
+        self.directions &= ~(1 << pin)  # 0 = output
+        self._write_reg(self.REG_CONFIG, self.directions)
+
+    def get_input(self, pin):
+        """Read pin (0-7); pin must be configured as input (the default)."""
+        return bool(self._read_reg(self.REG_INPUT) & (1 << pin))