Blinking color for some time

Hello there,
Although I thought this was easy, I couldn't do well. So please anyone, help me.

I want an object to blink black and white for ten seconds when I touched it.

integer condition;

default
{
    touch_start(integer total_number)
    {
        llSetTimerEvent(10);
        do
        {
            llSetColor(<0, 0, 0>, ALL_SIDES);
            llSleep(0.1);
            llSetColor(<1, 1, 1>, ALL_SIDES);
            llSleep(0.1);
        }
        while(!condition);
    }
    timer()
    {
        condition = !condition;
    }
}

I don't know how to use do-while loop correctly, either. I thought that it would stop when condition was changed, but it didn't. Please help me. Thanks.