ubuff = &u0buff;
       ubuff->tx_buff = u0_buff_tx;
       ubuff->rx_buff = u0_buff_rx;
    ubuff->tx_buff_size = sizeof(u0_buff_tx);
    ubuff->rx_buff_size = sizeof(u0_buff_rx);
    PCONP_bit.PCURT0 = 1; //UART power on
    PINSEL0_bit.P0_0 = 1;//select pin for UART0  
    PINSEL0_bit.P0_1 = 1;
    U0FCR = 0xC1;
    uart_bautrate(UART0,32);
    U0LCR = 0x03; //1-8-N
    INT_Plug(UART0_ISR,VIC_UART0,IRQ_int,IRQ_Slot0);
    VIC_IntEnable(BIT(VIC_UART0));
    U0IER_bit.RDAIE = 1;
    U0IER_bit.RXLSIE = 1;

int uart_send_str(TUartChanel dev, const char* data)
{
  TUART_BUFF* ubuff;
  int len,fsize,head,i;
  unsigned long old_irq;
  char *ptr;
  ubuff = &u0buff;
  fsize = 0;
  len = strlen(data);
  ptr = (char*)data;
  do
   {
    do fsize = uart_tx_free(dev); while(fsize == 0);
    if (fsize > len) fsize = len;
    head = ubuff->tx_head;
    for (i=0;i<fsize;i++)
     {
      ubuff->tx_buff[head] = *ptr++;
      if(++head == ubuff->tx_buff_size) head = 0;
     }
    ubuff->tx_head = head;
    old_irq = disable_IRQ();
    ubuff->tx_size = ubuff->tx_size+i;
    restore_IRQ(old_irq);
    U0IER_bit.THREIE = 1; //<= включаем прерывание и оно не происходит
    len = len - fsize;    
   }
  while((*ptr!='\0')&&(len > 0));
  return(0);
};

  //U0THR = 0x00;  //<- если включить эту строку UART начинает генерить прерывания
  while(1)
   {
     uart_send_str(UART0,"HELLO WORD");
   }

void UART0_ISR (void)
{
unsigned int tmp;
TUART_BUFF* ubuff = &u0buff;  
switch((U0IIR>>1)&0x7)
  {
   case IIR_THRE:   // continue sending data
        if (ubuff->tx_size == 0)U0IER_bit.THREIE = 0;
        else
         {
          U0THR = ubuff->tx_buff[ubuff->tx_tail];  
          ubuff->tx_size--;
          if (++ubuff->tx_tail == ubuff->tx_buff_size) ubuff->tx_tail = 0;
         }  
        break;
   case IIR_RSL:    
        tmp = U0LSR;
        ubuff->last_error |= tmp & 0x9E;
        break;
   case IIR_RDA:    // receive data
   case IIR_CTI:    // time out
        tmp = U0RBR;
        if (ubuff->eho_state == ON)
         {
          while(!U0LSR_bit.THRE);
          U0THR = tmp;
         };    
        if ((tmp == 0x0D) || (tmp == 0x0A)) ubuff->str_flag = 1;
        if (ubuff->rx_size == (ubuff->rx_buff_size-1))
         {
          ubuff->last_error |= RC_FIFO_OVERRUN_ERR;
         }
        else
         {
          ubuff->rx_buff[ubuff->rx_head] = tmp;    
          ubuff->rx_size++;
          if (++ubuff->rx_head == ubuff->rx_buff_size) ubuff->rx_head = 0;
         }
        break;
   }//switch
}  //isr