Constants and System Info (FmrbConst / FmrbHw)¶

Note

Under construction.

FmrbConst¶

A module that provides constants referenced throughout the system.

Platform Information¶

Constant	Value
`FmrbConst::PLATFORM`	`"linux"` or `"esp32"`
`FmrbConst::OS_VERSION`	OS version string
`FmrbConst::GA_VERSION`	fmruby-graphics-audio version
`FmrbConst::LINK_VERSION`	UART link protocol version
`FmrbConst::IDF_VERSION`	ESP-IDF version

Hardware Information¶

Constant	Description
`FmrbConst::MAC_ADDRESS`	MAC address string
`FmrbConst::CHIP_MODEL`	e.g. `"ESP32-S3"`
`FmrbConst::CHIP_REVISION`	Revision number
`FmrbConst::CHIP_CORES`	Number of cores
`FmrbConst::FLASH_SIZE_MB`	Flash capacity (MB)
`FmrbConst::PSRAM_SIZE_MB`	PSRAM capacity (MB)
`FmrbConst::RESET_REASON`	Reason for the last reset

Process Management¶

Constant	Purpose
`FmrbConst::PROC_ID_KERNEL`	Kernel process ID
`FmrbConst::PROC_ID_HOST`	Host process ID
`FmrbConst::PROC_ID_SYSTEM_APP`	System app ID
`FmrbConst::PROC_ID_USER_APP0` / `USER_APP1` / `USER_APP2`	User app slots

Process States¶

Constant
`PROC_STATE_FREE`
`PROC_STATE_INIT`
`PROC_STATE_RUNNING`
`PROC_STATE_SUSPENDED`
`PROC_STATE_STOPPING`

Messaging¶

Constant	Purpose
`MSG_TYPE_APP_CONTROL`	App control message
`MSG_TYPE_APP_GFX`	Graphics message
`MSG_TYPE_APP_AUDIO`	Audio message
`MSG_TYPE_HID_EVENT`	HID event (keyboard, etc.)

App Control Commands¶

Constant
`APP_CTRL_SPAWN`
`APP_CTRL_KILL`
`APP_CTRL_SUSPEND`
`APP_CTRL_RESUME`

Theme Colors (System-wide Color Scheme)¶

Constant	Purpose
`THEME_DESKTOP_BG`	Desktop background
`THEME_MENU_BG`	Menu background
`THEME_WINDOW_BG`	Window background
`THEME_TEXT`	Normal text
`THEME_TEXT_LIGHT`	Light text
`THEME_HIGHLIGHT`	Highlight
`THEME_BORDER`	Border
`THEME_BUTTON`	Button

These are all RGB332 values. Use them when you want your app's UI to match the OS color scheme.

Input Device: Keyboard (`KEY_*`)¶

USB HID Usage IDs. Compare with ev[:scancode] in on_event(ev).

Category	Constants
Letters	`KEY_A` .. `KEY_Z`
Numbers	`KEY_1` .. `KEY_9`, `KEY_0`
Control	`KEY_ENTER`, `KEY_ESC`, `KEY_BACKSPACE`, `KEY_TAB`, `KEY_SPACE`
Symbols	`KEY_MINUS`, `KEY_EQUAL`, `KEY_LBRACKET`, `KEY_RBRACKET`, `KEY_BACKSLASH`, `KEY_SEMICOLON`, `KEY_QUOTE`, `KEY_GRAVE`, `KEY_COMMA`, `KEY_PERIOD`, `KEY_SLASH`
Locks	`KEY_CAPSLOCK`, `KEY_SCROLLLOCK`, `KEY_NUMLOCK`
Function	`KEY_F1` .. `KEY_F12`
Editing	`KEY_INSERT`, `KEY_HOME`, `KEY_PGUP`, `KEY_DELETE`, `KEY_END`, `KEY_PGDN`
Arrow	`KEY_LEFT`, `KEY_RIGHT`, `KEY_UP`, `KEY_DOWN`
Other	`KEY_PRINTSCREEN`, `KEY_PAUSE`
Modifier keys (individual)	`KEY_LCTRL`, `KEY_LSHIFT`, `KEY_LALT`, `KEY_LGUI`, `KEY_RCTRL`, `KEY_RSHIFT`, `KEY_RALT`, `KEY_RGUI`

Input Device: Modifier Key Masks (`MOD_*`)¶

Use bitwise AND with ev[:modifier] in on_event(ev) to check modifier state.

Constant	Bit	Meaning
`MOD_LCTRL`	0x01	Left Ctrl
`MOD_LSHIFT`	0x02	Left Shift
`MOD_LALT`	0x04	Left Alt
`MOD_LGUI`	0x08	Left GUI (Win / Cmd)
`MOD_RCTRL`	0x10	Right Ctrl
`MOD_RSHIFT`	0x20	Right Shift
`MOD_RALT`	0x40	Right Alt
`MOD_RGUI`	0x80	Right GUI
`MOD_CTRL`	0x11	Combined left/right Ctrl (`MOD_LCTRL \| MOD_RCTRL`)
`MOD_SHIFT`	0x22	Combined left/right Shift
`MOD_ALT`	0x44	Combined left/right Alt
`MOD_GUI`	0x88	Combined left/right GUI

ev_ctrl?(ev) / ev_shift?(ev) / ev_alt?(ev)

You can also check modifiers using FmrbApp helpers. Using MOD_* directly is only needed for special cases; normally use the helpers instead.

Input Device: Gamepad (`GP_*`)¶

In on_event(ev), when ev[:type] == :gamepad_down / :gamepad_up, ev[:button] holds the button number. When ev[:type] == :gamepad_axis, ev[:axis] holds the axis number.

Buttons¶

Constant	Value	Meaning
`GP_SQUARE`	0	Square
`GP_CROSS`	1	Cross
`GP_CIRCLE`	2	Circle
`GP_TRIANGLE`	3	Triangle
`GP_L1`	4	Left shoulder
`GP_R1`	5	Right shoulder
`GP_L2`	6	Left trigger
`GP_R2`	7	Right trigger
`GP_SELECT`	8	Select
`GP_START`	9	Start
`GP_L3`	10	Left stick press
`GP_R3`	11	Right stick press
`GP_UP`	12	D-pad up
`GP_DOWN`	13	D-pad down
`GP_LEFT`	14	D-pad left
`GP_RIGHT`	15	D-pad right

Axes¶

Constant	Value	Meaning
`GP_AXIS_LX`	0	Left stick X
`GP_AXIS_LY`	1	Left stick Y
`GP_AXIS_RX`	2	Right stick X
`GP_AXIS_RY`	3	Right stick Y

Sample: Key Detection¶

def on_event(ev)
  super
  if ev[:type] == :key_down
    case ev[:scancode]
    when FmrbConst::KEY_LEFT  then @x -= 4
    when FmrbConst::KEY_RIGHT then @x += 4
    when FmrbConst::KEY_SPACE then shoot
    when FmrbConst::KEY_ESC   then stop
    end
    if (ev[:modifier] || 0) & FmrbConst::MOD_CTRL != 0 &&
       ev[:scancode] == FmrbConst::KEY_S
      save_state
    end
  elsif ev[:type] == :gamepad_down
    case ev[:button]
    when FmrbConst::GP_CROSS  then jump
    when FmrbConst::GP_START  then pause
    end
  end
end

Other¶

Constant	Description
`MAX_PATH_LEN`	Maximum path length

Sample: Display Version and Environment¶

class SysInfo < FmrbApp
  def on_create
    clear_user_area(FmrbGfx::WHITE)
    x = @user_area_x0 + 4
    y = @user_area_y0 + 4
    @gfx.draw_text(x, y,      "OS: #{FmrbConst::OS_VERSION}", FmrbGfx::BLACK)
    @gfx.draw_text(x, y + 10, "Chip: #{FmrbConst::CHIP_MODEL}", FmrbGfx::BLACK)
    @gfx.draw_text(x, y + 20, "PSRAM: #{FmrbConst::PSRAM_SIZE_MB}MB", FmrbGfx::BLACK)
    @gfx.draw_text(x, y + 30, "MAC: #{FmrbConst::MAC_ADDRESS}", FmrbGfx::BLACK)
    draw_window_frame
    @gfx.present
  end
end

SysInfo.new.start

FmrbHw¶

A module for querying the usage status of hardware resources (especially GPIO pins).

Method	Return Value
`FmrbHw.pin_status(pin)`	Pin usage state (`Integer`, 0 = unused, other = usage-specific identifier)
`FmrbHw.pin_available?(pin)`	`true` if unused
`FmrbHw.pin_status_all`	`Array<Integer>` (index = pin number, value = status)
`FmrbHw.pin_count`	Total number of pins

The value from pin_status is an internal identifier: 0 = unused, anything else = in use by another function such as "GPIO", "I2C", "UART", etc.

Sample: Display All Pins¶

status = FmrbHw.pin_status_all
status.each_with_index do |s, i|
  Log.info("pin #{i}: #{s == 0 ? 'free' : 'used'}")
end

Sample: Check Before Use¶

PIN = 10
unless FmrbHw.pin_available?(PIN)
  Log.error("Pin #{PIN} is in use (status=#{FmrbHw.pin_status(PIN)})")
  return
end
gpio = GPIO.new(PIN, GPIO::OUT)

There is a sample in tool/gpio_viewer.app.rb that visualizes pin states with a GUI.

For pin specifications (electrical characteristics, external connections), see Hardware
For GPIO usage, see Peripherals