if(!pthread_mutex_lock(&UART_WriteMutex)){
prevstate=uartDevWriteBuf_plc_state;
uartDevWriteBuf_plc_state = LOCKED;
pthread_mutex_unlock(&UART_WriteMutex);
uartDevWriteBuf_plc_state = FULL;
pthread_mutex_lock(&UART_WakeCondLock);
pthread_cond_signal(&UART_WakeCond);
pthread_mutex_unlock(&UART_WakeCondLock);