MicroPythonOS · jedie · Mar 31, 2026 · Mar 31, 2026 · Mar 31, 2026
diff --git a/internal_filesystem/lib/mpos/board/cyd.py b/internal_filesystem/lib/mpos/board/cyd.py
@@ -0,0 +1,174 @@
+print("cyd.py initialization")
+"""
+Cheap Yellow Display:
+    https://github.com/witnessmenow/ESP32-Cheap-Yellow-Display
+Tested with "ESP32-2432S028"
+
+ * Display: ili9341 320x240
+ * Touch: xpt2046
+
+Original author: https://github.com/jedie
+"""
+
+import time
+
+import drivers.display.ili9341 as ili9341
+import lcd_bus
+import lvgl as lv
+import machine
+import mpos.ui
+from drivers.indev.xpt2046 import XPT2046
+from machine import ADC, Pin
+from micropython import const
+from mpos import InputManager
+
+# Display (HSPI)
+SPI_HOST = const(0)
+SPI_FREQ = const(8_000_000)  # 8MHz max for ILI9341
+SPI_DC = const(2)  # TFT_RS / TFT_DC
+SPI_CS = const(15)  # TFT_CS
+SPI_RST = const(15)  # No reset pin, so use CS pin
+SPI_SCK = const(14)  # TFT_SCK
+SPI_MISO = const(12)  # TFT_SDO / TFT_MISO
+SPI_MOSI = const(13)  # TFT_SDI / TFT_MOSI
+
+BACKLIGHT_PIN = const(21)  # TFT_BL (also on P3)
+DISPLAY_WIDTH = const(320)
+DISPLAY_HEIGHT = const(240)
+LCD_TYPE = const(2)  # ILI9341 type 2
+
+# Touch Screen (XPT2046)
+TOUCH_SPI_HOST = const(1)
+TOUCH_SPI_FREQ = const(1_000_000)  # 1MHz
+TOUCH_SPI_SCK = const(25)
+TOUCH_SPI_MOSI = const(32)
+TOUCH_SPI_MISO = const(39)
+TOUCH_SPI_CS = const(33)
+TOUCH_SPI_INT = const(36)
+
+# SD Card (VSPI)
+SDCARD_SLOT = const(2)
+SDCARD_SCK = const(18)
+SDCARD_MISO = const(19)
+SDCARD_MOSI = const(23)
+SDCARD_CS = const(5)
+
+# RGB LED (active low)
+LED_RED = const(4)
+LED_GREEN = const(16)
+LED_BLUE = const(17)
+
+# Light Sensor
+LIGHTSENSOR_ADC_PIN = const(34)
+
+# Speaker (amplified)
+SPEAKER_PIN = const(26)
+
+# Buttons
+BUTTON_BOOT = const(0)
+
+# Connectors
+P3_IO35 = const(35)  # Input only
+P3_IO22 = const(22)
+CN1_IO22 = const(22)
+CN1_IO27 = const(27)
+P1_IO1 = const(1)  # TX (maybe usable as GPIO)
+P1_IO3 = const(3)  # RX (maybe usable as GPIO)
+
+
+# RGB LED at the back
+red_led = Pin(LED_RED, Pin.OUT)
+green_led = Pin(LED_GREEN, Pin.OUT)
+blue_led = Pin(LED_BLUE, Pin.OUT)
+
+# RGB LED (and backlight) will also work with machine.PWM for dimming
+
+# Turn on all LEDs (active low):
+red_led.on()
+green_led.on()
+blue_led.on()
+
+
+# Read light sensor
+lightsensor = ADC(LIGHTSENSOR_ADC_PIN, atten=ADC.ATTN_0DB)
+print(f"{lightsensor.read_uv()=}")
+
+
+print("cyd.py machine.SPI.Bus() initialization")
+try:
+    spi_bus = machine.SPI.Bus(
+        host=TOUCH_SPI_HOST, sck=SPI_SCK, mosi=SPI_MOSI, miso=SPI_MISO
+    )
+except Exception as e:
+    print(f"Error initializing SPI bus: {e}")
+    print("Attempting hard reset in 3sec...")
+    time.sleep(3)
+    machine.reset()
+
+print("cyd.py lcd_bus.SPIBus() initialization")
+display_bus = lcd_bus.SPIBus(spi_bus=spi_bus, freq=SPI_FREQ, dc=SPI_DC, cs=SPI_CS)
+
+print("cyd.py ili9341.ILI9341() initialization")
+try:
+    mpos.ui.main_display = ili9341.ILI9341(
+        data_bus=display_bus,
+        display_width=DISPLAY_WIDTH,
+        display_height=DISPLAY_HEIGHT,
+        color_space=lv.COLOR_FORMAT.RGB565,
+        color_byte_order=ili9341.BYTE_ORDER_BGR,
+        rgb565_byte_swap=True,
+        reset_pin=SPI_RST,
+        reset_state=ili9341.STATE_LOW,
+        backlight_pin=BACKLIGHT_PIN,
+        backlight_on_state=ili9341.STATE_PWM,
+    )
+except Exception as e:
+    print(f"Error initializing ILI9341: {e}")
+    print("Attempting hard reset in 3sec...")
+    time.sleep(3)
+    machine.reset()
+
+
+print("cyd.py display.init()")
+mpos.ui.main_display.init(LCD_TYPE)
+mpos.ui.main_display.set_power(True)
+mpos.ui.main_display.set_color_inversion(False)
+mpos.ui.main_display.set_backlight(100)
+
+print("cyd.py lv.init() initialization")
+lv.init()
+
+print("cyd.py Touch initialization")
+touch_dev = machine.SPI.Device(spi_bus=spi_bus, freq=TOUCH_SPI_FREQ, cs=TOUCH_SPI_CS)
+
+indev = XPT2046(
+    touch_dev,
+    lcd_cs=SPI_CS,
+    touch_cs=TOUCH_SPI_CS,
+    display_width=DISPLAY_WIDTH,
+    display_height=DISPLAY_HEIGHT,
+    startup_rotation=lv.DISPLAY_ROTATION._0,
+)
+
+
+group = lv.group_create()
+group.set_default()
+#
+# # Create and set up the input device
+# indev = lv.indev_create()
+# indev.set_type(lv.INDEV_TYPE.KEYPAD)
+#
+indev.set_group(
+    group
+)  # is this needed? maybe better to move the default group creation to main.py so it's available everywhere...
+# disp = lv.display_get_default()  # NOQA
+# indev.set_display(disp)  # different from display
+indev.enable(True)  # NOQA
+InputManager.register_indev(indev)
+
+# Turn off all LEDs to indicate initialization is done:
+red_led.off()
+green_led.off()
+blue_led.off()
+
+print("\ncyd.py init finished\n")
diff --git a/internal_filesystem/lib/mpos/main.py b/internal_filesystem/lib/mpos/main.py
@@ -172,6 +172,10 @@ def detect_board():
         if unique_id_prefixes == b'\x30\xae\xa4':
             return "odroid_go"
 
+        print("cyd - Cheap Yellow Display ?")
+        if unique_id_prefixes == b'\xec\xe34': # FIXME: Use other detection! MAC seems to be random!
+            return "cyd"
+
         # Do I2C-based board detection
         # IMPORTANT: ESP32 GPIO 6-11 are internal SPI flash pins and will cause WDT reset if used.
         # ESP32-S3 has more usable GPIOs (up to 48). Detect chip variant first to skip unsafe probes.
@@ -247,6 +251,9 @@ def detect_board():
     print(f"Detected {board} system, importing mpos.board.{board}")
     DeviceInfo.set_hardware_id(board)
     __import__(f"mpos.board.{board}")
+else:
+    # It makes no sense to continue, because we have no display etc...
+    raise RuntimeError("No board detected, exit initialization!")
 
 # Allow LVGL M:/path/to/file or M:relative/path/to/file to work for image set_src etc
 import mpos.fs_driver

diff --git a/internal_filesystem/main.py b/internal_filesystem/main.py
@@ -28,4 +28,11 @@
 )
 
 print("Passing execution over to mpos.main")
-import mpos.main  # noqa: F401
+try:
+    import mpos.main  # noqa: F401
+except Exception as e:
+    sys.print_exception(e)
+    import time
+    print(f"Error in mpos.main, sleep for 5 seconds and end then...")
+    time.sleep(5)
+
diff --git a/scripts/build_mpos.sh b/scripts/build_mpos.sh
@@ -8,14 +8,15 @@ target="$1"
 buildtype="$2"
 
 if [ -z "$target" ]; then
-	echo "Usage: $0 target"
-	echo "Usage: $0 <esp32 or unix or macOS>"
-	echo "Example: $0 unix"
-	echo "Example: $0 macOS"
-	echo "Example: $0 esp32"
-	echo "Example: $0 esp32s3"
-	echo "Example: $0 unphone"
-	echo "Example: $0 clean"
+    echo "Usage: $0 target"
+    echo "Usage: $0 <esp32 or esp32-small or unix or macOS>"
+    echo "Example: $0 unix"
+    echo "Example: $0 macOS"
+    echo "Example: $0 esp32"
+    echo "Example: $0 esp32-small"
+    echo "Example: $0 esp32s3"
+    echo "Example: $0 unphone"
+    echo "Example: $0 clean"
 	exit 1
 fi
 
@@ -106,20 +107,27 @@ popd
 echo "Refreshing freezefs..."
 "$codebasedir"/scripts/freezefs_mount_builtin.sh
 
-if [ "$target" == "esp32" -o "$target" == "esp32s3" -o "$target" == "unphone" ]; then
-    partition_size="4194304"
-    flash_size="16"
+if [ "$target" == "esp32" -o "$target" == "esp32s3" -o "$target" == "unphone" -o "$target" == "esp32-small" ]; then
+	partition_size="4194304"
+	flash_size="16"
 	otasupport="--ota"
 	extra_configs=""
-    if [ "$target" == "esp32" ]; then
+	if [ "$target" == "esp32" ]; then
 		BOARD=ESP32_GENERIC
 		BOARD_VARIANT=SPIRAM
+	elif [ "$target" == "esp32-small" ]; then
+        # No PSRAM, so do not set SPIRAM-specific options
+		BOARD=ESP32_GENERIC
+		BOARD_VARIANT=
+		partition_size="3900000"
+		flash_size="4"
+		otasupport="" # too small for 2 OTA partitions + internal storage
 	else # esp32s3 or unphone
-	    if [ "$target" == "unphone" ]; then
-	        partition_size="3900000"
-	        flash_size="8"
+		if [ "$target" == "unphone" ]; then
+			partition_size="3900000"
+			flash_size="8"
 			otasupport="" # too small for 2 OTA partitions + internal storage
-        fi
+		fi
 		BOARD=ESP32_GENERIC_S3
 		BOARD_VARIANT=SPIRAM_OCT
 		# These options disable hardware AES, SHA and MPI because they give warnings in QEMU: [AES] Error reading from GDMA buffer
@@ -128,6 +136,12 @@ if [ "$target" == "esp32" -o "$target" == "esp32s3" -o "$target" == "unphone" ];
 		# --py-freertos: add MicroPython FreeRTOS module to expose internals
 		extra_configs="$extra_configs --py-freertos"
 	fi
+
+	if [ "$BOARD_VARIANT" == "SPIRAM" -o "$BOARD_VARIANT" == "SPIRAM_OCT" ]; then
+		# Camera only works on boards configured with spiram, otherwise the build breaks
+		extra_configs="$extra_configs USER_C_MODULE=$codebasedir/micropython-camera-API/src/micropython.cmake"
+	fi
+
 	manifest=$(readlink -f "$codebasedir"/manifests/manifest.py)
 	frozenmanifest="FROZEN_MANIFEST=$manifest" # Comment this out if you want to make a build without any frozen files, just an empty MicroPython + whatever files you have on the internal storage
 	echo "Note that you can also prevent the builtin filesystem from being mounted by umounting it and creating a builtin/ folder."
@@ -148,17 +162,17 @@ if [ "$target" == "esp32" -o "$target" == "esp32s3" -o "$target" == "unphone" ];
 	# CONFIG_FREERTOS_GENERATE_RUN_TIME_STATS=y
 	# CONFIG_ADC_MIC_TASK_CORE=1 because with the default (-1) it hangs the CPU
 	# CONFIG_SPIRAM_XIP_FROM_PSRAM: load entire firmware into RAM to reduce SD vs PSRAM contention (recommended at https://github.com/MicroPythonOS/MicroPythonOS/issues/17)
-	python3 make.py "$otasupport" --optimize-size --partition-size=$partition_size --flash-size=$flash_size esp32 BOARD=$BOARD BOARD_VARIANT=$BOARD_VARIANT \
-	    USER_C_MODULE="$codebasedir"/micropython-camera-API/src/micropython.cmake \
-	    USER_C_MODULE="$codebasedir"/secp256k1-embedded-ecdh/micropython.cmake \
-	    USER_C_MODULE="$codebasedir"/c_mpos/micropython.cmake \
-	    CONFIG_FREERTOS_USE_TRACE_FACILITY=y \
-	    CONFIG_FREERTOS_VTASKLIST_INCLUDE_COREID=y \
-	    CONFIG_FREERTOS_GENERATE_RUN_TIME_STATS=y \
-	    CONFIG_ADC_MIC_TASK_CORE=1 \
-	    $extra_configs \
-	    "$frozenmanifest"
-
+	set -x
+	python3 make.py $otasupport --optimize-size --partition-size=$partition_size --flash-size=$flash_size esp32 BOARD=$BOARD BOARD_VARIANT=$BOARD_VARIANT \
+		USER_C_MODULE="$codebasedir"/secp256k1-embedded-ecdh/micropython.cmake \
+		USER_C_MODULE="$codebasedir"/c_mpos/micropython.cmake \
+		CONFIG_FREERTOS_USE_TRACE_FACILITY=y \
+		CONFIG_FREERTOS_VTASKLIST_INCLUDE_COREID=y \
+		CONFIG_FREERTOS_GENERATE_RUN_TIME_STATS=y \
+		CONFIG_ADC_MIC_TASK_CORE=1 \
+		$extra_configs \
+		"$frozenmanifest"
+    set +x
 	popd
 elif [ "$target" == "unix" -o "$target" == "macOS" ]; then
 	manifest=$(readlink -f "$codebasedir"/manifests/manifest.py)