File content as of revision 0:325fcc4dca89:

/*
 * mbed Application program
 *      Check "System clock" frequency
 *
 * Copyright (c) 2015 Kenji Arai / JH1PJL
 *  http://www.page.sannet.ne.jp/kenjia/index.html
 *  http://mbed.org/users/kenjiArai/
 *      Created: may       18th, 2015
 *      Revised: may       18th, 2015
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include "mbed.h"

DigitalOut myled(LED1);

int main() {
    printf("\r\n Your mbed SysClock is %u Hz.\r\n", SystemCoreClock);
    while(true) {
        myled = !myled;
        wait(1.0);
    }
}

/* measured by JH1PJL on May 18th, 2015

 Check old revision
 Case L152
    before and rev.81 20140319  -> 16000000Hz
    rev.82 and after  20140407  -> 24000000Hz
 Case F401
    all rev.(?)                 -> 84000000Hz
 Case F411
    befoe and rev.97  20150414  -> 100000000Hz
    rev.98& 99 (as of 20150518) -> 96000000Hz
 Case LPC1768
    rev.99 -> 96000000Hz
 Case GR-PEACH
    error "SystemCoreClock" is undefined
 Case LPC1114FN28
    rev.99 -> 48000000Hz

 */