/* get feedback value from rate in USB full speed  */
static void get_feedback_fs_rate(uint32_t rate, uint8_t *buf)
/* get feedback value from rate in USB full speed  */
static void get_feedback_fs_rate(uint32_t rate, uint8_t *buf)
{
    rate = ((rate / 1000) << 14) | ((rate % 1000) << 4);
    buf[0] = rate;
    buf[1] = rate >> 8;
    buf[2] = rate >> 16;
}