Interrupt driven UART

[Altera_Forum]

Hello everybody, 

 I'm a NIOS II beginner and I'm having trouble in finding an example how to code an interrupt driven UART application where I can send and receive commands from a camera I have interfaced to the cyclone board RS232 serial port.   I would be grateful for any help  Thanks

[Altera_Forum]

This is non HAL code in NIOS1 but it is currently working fine in NIOS2 as well 

  include # include "excalibur.h"  global  //Make sure you have a uart in excalibur.h that matches your uart name (na_uartxxxx)  np_uart *uart1 = (np_uart *)na_uart_1;   init the uart  void uart1_setup(void) {    //UART 1 setup -----------------------    uart1->np_uartstatus = 0; // clear the interrupt condition    nr_installuserisr(na_uart_1_irq ,UART1_ISR,(int)uart1);    uart1->np_uartcontrol=0;  uart1->np_uartcontrol = uart1->np_uartcontrol | (np_uartcontrol_irrdy_mask);    }    irq routine  void UART1_ISR(int context) { np_uart *uart1 = (np_uart *)context;  int status; unsigned char rxChar;   status = uart1->np_uartstatus;  rxChar = (unsigned char)uart1->np_uartrxdata;    uart1->np_uartstatus = 0; // clear the interrupt condition     if(status & np_uartstatus_rrdy_mask) // character arrived?  {   // Write code to handle rxchar;  }   if(status & np_uartstatus_trdy_mask) // character arrived?  {   if (more bytes to transmit?)  {  // Write code to send next byte  uart1->np_uarttxdata=next byte   }  else  {  // Set the port to read only  uart1->np_uartcontrol = np_uartcontrol_irrdy_mask; //only Rx enable (if half duplex)   }     }   }    to start a transmit sequence start by sending a byte and then enabling the Tx IRQ flag.   uart1->np_uarttxdata=tx1_buffer[0]; // send first byte. IRQ will do the rest   uart1->np_uartcontrol =np_uartcontrol_itrdy_mask; // only Tx enable    you can have rx irq flag enabled all the time for full duplex. Just write your code to handle it.  First use a fix baud rate (as defined in SOPC builder) before playing with your own software settings. Fix baud rates uses less LEs.   to test connect the 2 pins (Tx,Rx) either in software or hardware and send a few bytes and return the status with a printf or 2.  To make life easier implement a ring buffer for the received character and parse it outside the irq. Don't put too much inside the IRQ routine. Just grab and store.  Victor http://www.zerksus.com (http://www.zerksus.com)