NiosII Uart Interrupt Handler

Hi everyone, I was directed here by a forumer Krasner when I posted my problem in this forum.

My current system is done with polling as mentioned earlier using direct register method (IORD_ALTERA_AVALON_UART_STATUS (UART_BASE);

IOWR_ALTERA_AVALON_UART_TXDATA(UART_BASE, txdata);etc)., now I would like to implement with interrupt as you recommended, but I have few issues I need to understand so that I can fix those errors:

I am able to read serial port and plot the graph real time in Matlab. However, I am having the issue where the data is not updated as frequent as desired. I am using USB-to-Serial interface to the board FTDI UM245R module.

I have a few questions about using interrupt for uart:

I want to send data from Nios II to serial port to plot graph real time in Matlab.

1. In function void InitUart(), what is the "Uart1_IRQ_INTERRUPT_CONTROLLER_ID" for? I read in the

I read in the Altera documentation (https://www.altera.com/en_us/pdfs/literature/hb/nios2/n2sw_nii52010.pdf), the interrupt controller ID is defined in system.h, but I couldn't find any info about it in system.h, should I generate or do something to get this controller id?

2. I assigned IRQ no.2 in Qsys, I dont understand how doesthe function in InitUart() know that Uart1_IRQ is 2? Is it done automatically or how should I assign?

alt_ic_isr_register(Uart1_IRQ_INTERRUPT_CONTROLLER_ID, Uart1_IRQ,IsrUart1,&context_uart,0x0);

alt_ic_irq_enable(Uart1_IRQ_INTERRUPT_CONTROLLER_ID, Uart1_IRQ);

3. i can't find how to set the flag to 0x0 as you have written

4. Regarding alt_ic_isr_register(Uart1_IRQ_INTERRUPT_CONTROLLER_ID, Uart1_IRQ,IsrUart1,&context_uart,0x0);,

I know this sounds stupicd, can I write the above line twelve times so I can call the function IsrUart1 twelve times? Reason being, I need to send twelve sets of data, imagine I have twelve sets of "context_uart" , each set of data has 10 elements for instance. If it is not possible to call alt_ic_isr_register for 12 times, is there a smart way to do it?

5. In the main function, why do we need the two functions GetUart1() and PutUart2()? I thought in the IsUart1(), we have already transmitted the data

6. My current system is done with polling as mentioned earlier, now I would like to implement with interrupt as you recommended, since the current system can display data in correct value and order, but data is not updated as frequent as desired (I posted the thread here http://www.alteraforum.com/forum/showthread.php?t=48165), so do you think I still need to have those codes for buffer size, head and tail etc?

In the function PutUart1(), if (++TxHead_1 > (TX_BUFFER_SIZE_1-1)) TxHead_1 = 0;

z = IORD_ALTERA_AVALON_UART_CONTROL(UART1_BASE) | ALTERA_AVALON_UART_CONTROL_TRDY_MSK;

IOWR_ALTERA_AVALON_UART_CONTROL(UART1_BASE, z);

I am wondering what is the purpose of having the codes checking the buffer size and the head and tail? TxHead_1==TxTail_1

7. divisor = (ALT_CPU_FREQ/BaudRate) +1; I assume I dont need this as I have fixed baud rate 115200, am I right?

I hope someone could just give short answer to my questions, really appreciate your help!!