File system driver

To use this package, go to https://makecode.microbit.org, click Extensions and search for filesystem.

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BETA - This package is still under development and subject to changes.

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Usage

The package allows to read and write files to the @boardname@ flash.

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The entire file system content is ERASED when a new .hex file is download onto the @boardname@.

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Writing data

• append text and a new line character

files.appendLine("data.txt", "Hello");

• append text to the file

files.appendString("data.txt", "Hello");

• append a number (as text) to the file

files.appendNumber("data.txt", 42);

Reading data

• send the content of a file to serial

files.readToSerial("data.txt");

Settings

The package allows to save and load number settings based on the file system

• save setting value

files.settingsSaveNumber("calibrated", 1)

• read setting value

let calibrated = files.settingsReadNumber("calibrated");

File class

The File class allows to keep a file instance open, manipulate the pointer position and read from the file.

• open, flush or close the file

let f = files.open("data.txt");
f.flush();
f.close();

• write strings or buffers

let f = files.open("data.txt");
f.writeString("yay");

• read data

let f = files.open("data.txt");
let buf = f.readBuffer(64);
let c = f.read();

• set the cursor position

let f = files.open("data.txt");
f.setPosition(42);
let pos = f.position();

Example: Writing accelerometer data

The following program allows to collect accelerometer data and save it in a data.csv file. When the user presses button A, the @boardname@ pauses for 3 seconds, then starts collecting 720 acceleration samples. Each sample is written to the file in a format that can be important by spreadsheet programs (CSV).

let file = "data.csv";
input.onButtonPressed(Button.A, () => {    
    basic.pause(3000);
    files.remove(file);
    files.appendLine(file, "Time\tAcceleration");
    for (let i = 0; i < 100; ++i) {
        let t = input.runningTime();
        let ay = input.acceleration(Dimension.Y);
        files.appendLine(file, t + "\t" + ay);
        control.waitMicros(20);
    }
});
input.onButtonPressed(Button.B, () => {
    files.readToSerial(file);
    basic.showString(":)")
})

Supported targets

• for PXT/ microbit
• for PXT/ calliope

License

MIT

Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.