How to set ISR in NiosII?

Hi,

Read the "NIOS II Software Developpers Handbook", part 6 "Exception handling".

There is an example on page 6-10 for the PIOs.

In place of

nr_installuserisr ()

I think that you have to use

alt_irq_register ()

Regards,

Jean LEE

Thanks Jean LEE!

But I have noticed that there only an example about PIO,

instead of UART. Are their relevent routines the same?

I wonder whether the UART's ISR routines in NiosII go the

same as their counterparts in NiosI?

This is a part of my operation of ISR in the main() routine:

alt_irq_register(MY_UART_IRQ, (void*) &context, my_rxd);

IOWR_ALTERA_AVALON_UART_CONTROL(MY_UART_BASE, ALTERA_AVALON_UART_STATUS_RRDY_MSK);

Is the second sentence correct?

I &#39;m not so sure... http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/huh.gif

Don,

Why do you want to write your own ISR for the UART?

The HAL already contains code for this and, if you use the IDE flow, it&#39;s likely you already have an ISR registered for the UART. Read through the section in the manual regarding the UART and you&#39;ll see what I mean. Unless you&#39;ve disabled it, all interrupt-capable components will have registered ISRs following alt_sys_init().

Cheers,

- slacker

Hi Slacker,

Sorry,perhaps I did not describe my problem explicitly,

what I want is not writing a sheer ISR by myself, but I just want to

take advantage of the ISR routines which are the NiosII provided

and available to be used.

The code I posted above previously is

alt_irq_register(MY_UART_IRQ, (void*) &context, my_rxd);

IOWR_ALTERA_AVALON_UART_CONTROL(MY_UART_BASE, ALTERA_AVALON_UART_STATUS_RRDY_MSK);

I really don&#39;t know whether I &#39;m on the right way or not,

could you give me some suggestions about that?

Besides, I redirect my stdin and stdout in my system library properties

both to "my_uart", is that right?

Many thanks!

Regards,

Don

Hi,

But the current device I&#39;m tinkering with is a custom UART.

I think there are two conventional approaches to receive data from that.

One approach is through Interruption by registering the

device with a ISR,and when a char comes in,the program

would automatically jump into the receiver ISR and operate

the code just received.

The other alternative is requiring the relevent register(or checking the state),

such as RRDY in the status register.

But now, though both of the approaches I have tried,

the UART device cannot receive any char,I really cannot figure out why.

1)The code for the first approach is like this :

------------

(the code in main)

alt_irq_register(GSM_UART_IRQ, (void*) &context, gsm_rxd);

IOWR_ALTERA_AVALON_UART_CONTROL(GSM_UART_BASE, ALTERA_AVALON_UART_STATUS_RRDY_MSK);

------------

and

------------

(the receiver ISR)

void gsm_rxd(void* context, alt_u32 id)

{

rxbuffer[rxhead]= IORD(GSM_UART_BASE,0);

IOWR_ALTERA_AVALON_UART_STATUS(GSM_UART_BASE, 0);

printf("The char received are %c\n",rxbuffer[rxhead]);

if( (++rxhead) > (SIZE-1) )

rxhead=1;

}

------------

2)And the code for the second approach is like following:

------------

void gsm_rxd()

{

while((IORD(GSM_UART_BASE,2)&0x80)!=0x80)

;

rxbuffer[rxhead]= IORD(GSM_UART_BASE,0);

printf("\nThe order received is:\n");

//printf("%x",IORD(GSM_UART_BASE,0));

printf("%x",rxbuffer[rxhead]);

IOWR_ALTERA_AVALON_UART_STATUS(GSM_UART_BASE, 0);

if( (++rxhead) > (SIZE-1) )

rxhead=1;

}

-------------

Please help me to figure out why the two type of routines

just do not work. http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/huh.gif

Besides, the transmitting routine I wrote is like this:

--------------

void gsm_txd(char data[],char length)

{

volatile char m;

printf("\nThe command sent is:\n");

for(m=0;m<length;m++)

{

while((IORD(GSM_UART_BASE,2)&0x40)!=0x40)

;

IOWR(GSM_UART_BASE,1,data[m]);

printf("%c",IORD(GSM_UART_BASE,1));

}

}

Because it works so fine when it operates, so I

made a receiving routine following the pattern of the

transmitting routine, which is the code 2) I just wrote above.

So the second question is why this receiver

function do not work as its counterpart as a

transimitter routine?

Thank you for your suggestions and helps... http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/wink.gif

Regards,

Don

If you wish to use an ISR you only need to call alt_irq_register as you do in your example 1.

It sounds to me like you either have a problem with your hardware or how you&#39;re controlling it, you need to look with the debugger to see if you&#39;re ever getting into your ISR and if not is the bit corresponding to your UART&#39;s IRQ getting set in the ipending register?

Also I notice you&#39;re using printf inside your ISR you can&#39;t rely on this working.

--- Quote Start ---

originally posted by rugbybloke@Aug 12 2005, 04:22 AM

if you wish to use an isr you only need to call alt_irq_register as you do in your example 1.

it sounds to me like you either have a problem with your hardware or how you&#39;re controlling it, you need to look with the debugger to see if you&#39;re ever getting into your isr and if not is the bit corresponding to your uart&#39;s irq getting set in the ipending register?

also i notice you&#39;re using printf inside your isr you can&#39;t rely on this working.

--- Quote End ---

Hi rugbybloke,

Thank you for your suggestions to me!

But I did use debugger in NiosII IDE to check my code,

but everytime after its sending AT command to the UART,

there always no response(It should response "OK" at least)

from that.And when the debugger comes to the breakpoint at the

---------------

while((IORD(GSM_UART_BASE,2)&0x80)!=0x80)

;

---------------

It would stop forever, without any forward actions any more.

Thus I really dont know where the rub of the code above is,

besides, are the code following right

when I register the interruption for my program?

--------------

alt_irq_register(GSM_UART_IRQ, (void*) &context, gsm_rxd);

IOWR_ALTERA_AVALON_UART_CONTROL(GSM_UART_BASE, ALTERA_AVALON_UART_STATUS_RRDY_MSK);

--------------

Because I have not used interruption in NiosII,

so I&#39;m not sure about that... http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/huh.gif

Many thanks!

Regards,

Don

Don,

Without knowing your hardware it&#39;s hard to comment further.

Your code is spinning permanently waiting for bit 7 of your register. Have you got the addresses right? Is this signal asserted? I suspect you either have faulty hardware or your addresses are wrong.