UDP buffer allocation fails

Where are you calling the UdpSend from?

Is it from within the callback?

Even if I comment out my udpsend I get an hardfault. But then all the ARP-stuff is done again.

Where are you calling udp_get_buf(len); from ?

In the same function as the udpsend(). I tried both: to call that function from the callback-function and also to call it from my udp_task but the effect was the same.

Here are the important parts of my code:

int main (void)
{
        InitDevice();
        init_TcpNet();

        /* Initialize UDP Socket and start listening */
        ucMainUDP_socket = udp_get_socket (0, UDP_OPT_SEND_CS | UDP_OPT_CHK_CS, UDP_callback);
        if (ucMainUDP_socket != 0)
        {
        udp_open (ucMainUDP_socket, UDP_PORT_NUM);
        }

        //---RTOS-Setup
        os_sys_init_prio(InitTask,250);                 // init RTOS with 'InitTask' as start-Task and prio of 250
}

__task void InitTask(void)
{
        // start 'UDPTask' with an priority of 100
        tID_UDPTask = os_tsk_create(UDPTask, 100);
        // start 'Timer'
        tID_TimerTask = os_tsk_create(tick_timer, 100);

        // we do not need 'InitTask' anymore
        os_tsk_delete_self();
}

__task void UDPTask(void)
{
        while(1)
        {
                main_TcpNet();
                os_tsk_pass ();
        }
}

__task void tick_timer (void) {
  os_itv_set (10);
  while (1) {
    os_itv_wait ();
    /* Timer tick every 100 ms */
    timer_tick ();
  }
}


unsigned short UDP_callback (unsigned char soc, unsigned char *rip, unsigned short rport, unsigned char *buf, unsigned short len)
{
        if (len < 10)
                return (0);

        if (soc != ucMainUDP_socket)
        {
        /* Check if this is the socket we are connected to */
        return (0);
        }

        procrec(buf,len);

        return (0);
}

void procrec (U8 *buf, unsigned short len)
{

        char udp_msg[]={"Hello World!"};
        static U8 remip[] = {192,168,240,77};
        U8 *sendbuf;
        U16 len1;

        len1 = strlen(udp_msg);
        if (ucMainUDP_socket != 0)
        {
//              sendbuf = udp_get_buf(13);
//              strcpy ((char*)sendbuf, udp_msg);
//              udp_send (ucMainUDP_socket, remip, 23456, sendbuf, len1);
        }
        return;

}

Is there an evident mistake?

A response I once got from Keil Technical Support was this:

In general the rule is "Do not call any TCP net functions from the TCP callback function." This is self explaining.

I would suggest that (as a test) you change your callback function to set a flag on receipt of the UDP message and test the flag for the generation of a response (including the call to udp_get_buf) within your UDPTask loop.

This is (fundamentally) what I do in my code.

Ok.
I set a flag. But it crashes when I leave the callback-function. I tried to do single-stepping and realized that after the callback I jump to the function: void int_disable_eth (void)
and in the following I get the fault. I think that there is basically an other problem as the call to udp_get_buf.

Thank you all for your help!
Finally I found the problem: my task didn't run in privileged mode! Now I can send UDP-data.

Hi Mike,

the remedy could be to run RTX in privilege mode or to modify int_enable_eth() and int_disable_eth() so that when they manipulate the NVIC they temporarily run in privileged mode.

I also had problems running TCPnet together with RTX on a Cortex M3. That was strange because I had always used that on ARM7s. Finally, I saw the very same crash as yours on int_disable_eth(), looked at the code inside and it flashed a light: the NVIC and the privileged mode!

I cannot say if your program has other problems, but on a project of mine which successfully uses TCPnet and RTX in protected mode on a CM3, if I turn protected mode off the program crashes.

Regards, Marco.

OK... I was late.

The important thing however, is that you solved your problem.

Cheers, Marco.

Thanks for mentioning the solution.

I haven't (yet) had the chance to use the Cortex-M3. Our projects have been on ARM7 and ARM9 and I've never needed to do anything special with regards to the privilege mode.

I'll write myself a reminder for the future.