MicroPython SDK - Embedded Reference

The firmware exposes a single ferret module with all drawing, input and helper functions built in. Import it at the top of your game script with:

import ferret

All colours are RGB565 integers; use ferret.rgb_to_565(r, g, b) to build one from 8-bit channels. The screen is 240x240 pixels.

Drawing

Drawing calls update a frame buffer in RAM. Call ferret.present() to send it to the screen.

ferret.pixel

Arguments: x, y, colour.

Draws a single pixel.

ferret.fill_rect

Arguments: x, y (top left corner), width, height, colour.

Draws a filled rectangle.

ferret.fill

Argument: colour.

Fills the whole screen with a single colour. Useful to clear the frame between frames.

ferret.draw_text

Arguments: text, x, y, colour.

Draws text at the top-left coordinate x, y. A single character is 8x8.

ferret.measure_text

Argument: text. Returns (width, height).

Measures the space text will take up, so you can centre it.

ferret.draw_image

Arguments: image_name, x, y.

Draws an image stored on the device at (x, y). The size is read from the image manifest, so sync your images from the web editor first. Transparent pixels use the RGB565 chroma key colour 0xF81F and are skipped (if you are using the web editor, this is done automatically for transparent pixels). No image can be over 240x240 pixels.

ferret.present

No arguments.

Flushes the frame buffer to the display.

Input

Call ferret.input_update() once per frame before checking buttons. Key names are strings. Both boards provide “A”, “B”, “UP”, “DOWN”, “LEFT” and “RIGHT”. Version one additionally provides “START” and “EXIT”; version two provides “X”, “Y” and “MENU” instead.

ferret.input_is_pressed

Argument: key name. Returns a bool.

True if the key is currently held.

ferret.input_was_just_pressed

Argument: key name. Returns a bool.

True if the key is pressed this frame but was not last frame.

ferret.input_was_just_released

Argument: key name. Returns a bool.

True if the key was pressed last frame but is not this frame.

Helpers

ferret.rgb_to_565

Arguments: r, g, b. Returns an RGB565 colour.

ferret.random_int

Arguments: min, max. Returns a random integer in the inclusive range [min, max].

Example

import ferret

while True:
    ferret.input_update()
    if ferret.input_was_just_pressed("A"):
        ferret.fill(ferret.rgb_to_565(255, 0, 0))
        ferret.present()

Files and editor functions (not user facing, you should not need these)

The editor also uses ferret.write_file_b64, ferret.append_file_b64, ferret.file_manifest, ferret.delete_file, ferret.write_image, ferret.append_image, ferret.write_image_end, ferret.image_manifest and ferret.delete_image to save code and sync images. Games do not normally need to call these functions themselves. A single file is currently limited to 16KiB. Normal Python open() and os filesystem access is not included.