Mbed has stopped to be recognized as USB disk

19 Jun 2010

I downloaded some examples programs in the last weeks and all worked fine. Then, I downloaded the example program with Nokia display.

#include "mbed.h"
#include "NokiaLCD.h"

NokiaLCD lcd(p5, p7, p8, p9); // mosi, sclk, cs, rst

int main() {
    lcd.fill(2, 51, 128, 10, 0x00FF00);
    lcd.fill(50, 1, 10, 128, 0xFF0000);
    lcd.printf("Hello World!");
    for (int i=0; i<130; i++) {
        lcd.pixel(i, 80 + sin((float)i / 5.0)*10, 0x000000);

Mbed executes the program but after having pressed several times the reset button,I am not able to see the MBED as a disk and and to change the program.Is there a recovery procedure?

19 Jun 2010

Hi Gabriele,

If you hold down the reset button continuously while you connect the usb (and after it is connected), you will hold the mbed in reset. This should allow you to see the mbed as a disk again, should any running program on the mbed be interfering with that.


20 Jun 2010

If you are using a trim pot to control the contrast make sure it is not turned all the way in so as to short ot the conneced supply pin.  To check this remove contrast pot and try again.