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USBKeyboard

Table of Contents

  1. Hello World
  2. API
  3. More examples
  4. Related

The USBKeyboard interface is used to emulate a keyboard over the USB port. You can type strings and send keycodes, send keys with modifiers (e.g. CTRL + 's'), function keys and also the media control keys

The USB connector should be attached to p31 (D+), p32 (D-) and GND. You can also connect the USB power to VIN to power the mbed when connected.

Hello World

USBKeyboard Hello World

#include "mbed.h"
#include "USBKeyboard.h"

//LED1: NUM_LOCK
//LED2: CAPS_LOCK
//LED3: SCROLL_LOCK
BusOut leds(LED1, LED2, LED3);

//USBKeyboard attached with led bus
USBKeyboard keyboard(&leds);

int main(void) {
    while (1) {
        keyboard.mediaControl(KEY_VOLUME_DOWN);
        keyboard.printf("Hello World from Mbed\r\n");
        keyboard.keyCode('s', KEY_CTRL);
        keyboard.keyCode(KEY_CAPS_LOCK);
        wait(1);
    }
}

Import programUSBKeyboard_HelloWorld

USBKeyboard Hello World

Last commit 01 Mar 2013 by Samuel Mokrani

Currently only available in betamode!

This library is in beta, and only works with the betamode compiler and the beta version of the libraries.

To use these examples, ensure you have enabled /betamode for the compiler, and then import these examples as the basis for your experiments to ensure the beta mbed library is pulled in.

API

Import library
USBDevice - USBKeyboard Class Reference

Public Member Functions

USBKeyboard (uint16_t vendor_id=0x1235, uint16_t product_id=0x0050, uint16_t product_release=0x0001)
Constructor.
bool keyCode (uint8_t key, uint8_t modifier=0)
To send a character defined by a modifier(CTRL, SHIFT, ALT) and the key.
virtual int _putc (int c)
Send a character.
bool mediaControl (MEDIA_KEY key)
Control media keys.
uint8_t lockStatus ()
Read status of lock keys.
bool send (HID_REPORT *report)
Send a Report.
bool sendNB (HID_REPORT *report)
Send a Report.
bool read (HID_REPORT *report)
Read a report: blocking.
bool readNB (HID_REPORT *report)
Read a report: non blocking.

More examples

Program which controls sound and tracks of your playlist with switches:

USBKeyboard and media keys

#include "mbed.h"
#include "USBKeyboard.h"

USBKeyboard keyboard;

//Bus of buttons
BusInOut buttons(p21, p22, p23, p24, p25, p26, p29);

int main(void) {
    uint8_t p_bus = 0;

    while (1) {
        //if the bus of buttons has changed, send a report
        if (buttons.read() != p_bus) {
            p_bus = buttons.read();
            if(p_bus & 0x01)
               keyboard.mediaControl(KEY_MUTE);
            if(p_bus & 0x02)
               keyboard.mediaControl(KEY_VOLUME_DOWN);
            if(p_bus & 0x04)
               keyboard.mediaControl(KEY_VOLUME_UP);
            if(p_bus & 0x08)
               keyboard.mediaControl(KEY_NEXT_TRACK);
            if(p_bus & 0x10)
               keyboard.mediaControl(KEY_PLAY_PAUSE);
            if(p_bus & 0x20)
               keyboard.mediaControl(KEY_PREVIOUS_TRACK);
            if(p_bus & 0x40)
               keyboard.printf("Hello World\r\n");
        }
        wait(0.01);
    }
}
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