void uart1_init(uint16_t uart1_div){

   // GPIO
   PD_DDR_bit.DDR5 = 1;   //TX for output
   PD_DDR_bit.DDR6 = 0;   //RX for input

   PD_CR1_bit.C16 = 0;      // floating RX
   PD_CR2_bit.C26 = 0;      // no external interrupts for RX

   // baud rate registers
   UART1_BRR2 = (uart1_div & 0x000f) | (uart1_div >> 12);
   UART1_BRR1 = (uart1_div >> 4) & 0x00ff;

   UART1_CR1_PIEN = 0;      // no parity
   UART1_CR1_PCEN = 0;      // no parity control
   UART1_CR1_M = 0;      // 8 bit
   UART1_CR1_UART0 = 0;   // switch uart ON

   UART1_CR2_TIEN = 0;      // no interrupt on tx buffer underflow
   UART1_CR2_TCIEN = 0;   // no interrupt on tx transfer complete

#ifdef UART1_RX_BUFFER_SIZE
   UART1_CR2_RIEN = 1;      // 0/1 no/yes interrupt on rx
   uart1_rx_clear();
#else
   UART1_CR2_RIEN = 0;      // 0/1 no/yes interrupt on rx
#endif

   UART1_CR2_ILIEN = 0;   // no interrupt on line free
   UART1_CR2_TEN = 1;      // switch on transmitter
   UART1_CR2_REN = 1;      // switch on receiver
   UART1_CR2_SBK = 0;      // no break char
   UART1_CR3_STOP = 0;      // 1 stop bit
}

#pragma vector=UART1_R_RXNE_vector
__interrupt void uart_rx_interrupt(void){
   uint8_t data = UART1_DR;
   //uart1_rx_push(data);
}