DAVE™ Forum Discussions

Hi MagicPhoton
I moved my answer here so it can help also other Dave user:

Hello,

I have programmed the example of WEBSERVER001_Example2 in XMC5400 Hexagon Application Kit but when you switch very fast the LED from the web page, the server stops working and you need to press reset button to restart it.

Could anyone give me any advice to manage the requests and not saturate the server?

Best regards,
MagicPhoton

Hi MagicPhoton,
after my vacation I have found the time fork a deeper analysis using a protocol analyzer: wireshark.
The issue seem related to lwip itself and windows.

My test enviroment:
windows7, firefox and webserver example.

Test:
Press multiple times and very quickly F5 that refresh the page
After around 30 times page refreshes, webserver answer is getting slower and if I proceed further with refresh, webserver/lwip is not responding any longer to firefox and ping.
If I wait 1-1.5 min the webserver recover and answer as usual to ping and browser request.

My analysis:
Page refresh slow answer is a know problem of lwip and this depends on the configuration see:

• http://lwip.100.n7.nabble.com/Slow-release-time-of-closed-TCP-PCBs-td8538.html
  
  
• http://comments.gmane.org/gmane.network.lwip.general/6727
  
• http://lists.gnu.org/archive/html/lwip-users/2011-04/msg00174.html
  

So in few words there are too many TCP connections and web server will reset any furtther connections and waiting a timeout to close old connection in wait to close state. (confirmed by wireshark)
After closing some of TCP connections lwip is able to accept new connections.

Why it is not answering to ping ?
I see that when webserver is no longer responding to new TCP connections windows is sending an ARP message (basically is asking confirmation of Ethernet mac address of the board); Lwip is not answering; windows after some tries thinks that there is not device with this mac address.
When I tries a ping or browser request I don't see any message sent by my PC because windows TCP/IP stack thinks that there is no device (my guess).
After 1-2mins I see windows a new arp message again now lwip answers and after this everything works fine.

Conclusion:
This test that I have done is like a Denial of Service (DoS) attack and lwip is reacting as already described. From the links I have found it looks like that if the developer would like to support more fast connection it have to reduce a timeout and/or increase the number of concurrent TCP open connections (not yet tried).

I think this explains that you have seen.
Regards
Oreste
PS. ETH004 use still old lwip 1.3.4 and not the latest version (at the time of app development was not yet stable) We have planned to updated to the latest maybe this will improve the situation. Show Less

This is what worked for me to get printf working with DAVE4.1.2 and XMC1100 (xmc2go).
If anyone has a better solution - please post it here...

/* This "wires" the putchar/printf functions to transmit to UART_0 */
int _write(int file, uint8_t *buf, int nbytes)
{
    if(UART_Transmit(&UART_0, buf, nbytes) == UART_STATUS_SUCCESS) {
       while(UART_0.runtime->tx_busy) {
        }
    }
    return nbytes;
}

/* This "wires" the getchar function to receive from UART_0 */
int _read(int file, uint8_t *buf, int nbytes)
{
    if(UART_Receive(&UART_0, buf, 1) != UART_STATUS_SUCCESS) {
      nbytes = 0;
    } else {
      nbytes = 1;
    }
	return nbytes;
}

best regards,
Tom Moxon
www.patternagents.com
@PatternAgents Show Less

I'm using DAVE4.1.4 and working on connecting several IOs to EVENT_DETECTORS

When using the HW Signal Connection dialog box, after selecting PIN for the source signal, I do not see the Event Detector APP in the pull down list.

Example is using the Relax Lite Kit where Button 1 and Button 2 are configured for pins 1.14 and 1.15 respectively.

Button_1 doesn't show the APP where Button 2 does.

Are there restriction that are not documented on which Pins can be used? Show Less

Hi,
I need a basic example (XMClib) of how to erase, program and read (in quad mode) the QSPI flash of the XMC4500 relax kit.

Is it possible to change the configuration of the example "QSPI_EXAMPLE_XMC45" of the DAVE-4.1.4 to work for the XMC4500 relax kit? If yes, how to do it?

Thanks,

Ari. Show Less

Hello All,

the Dave 4 installer wanted admin rights to install, and it installed the library store to c:\users\administrator\infineon

This way, I can't access the library store as other user.

Does anybody know the intention behind?

Any idea how I can access the library store?

Oliver Show Less

Hi,


I hit the following issue in Dave4 while developing a program for the XMC2Go. I added and configured a DIGITAL_IO app as an input pin, attached to port 0.14.
After this, it is not possible to add the SYSTIMER app, as the attempt fails with this error: "DAVE is not able to grant you last hardware resources request".

Looking into this, I discovered that the SYSTIMER app can only be added if the previous DIGITAL_IO app is not yet attached to a pin, but in this case the port 0.14 is no longer available for use as an input.
The reason for this is that the SYSTIMER app also includes the CPU_CTRL_XMC1 system app into the project, which defines the debug interface to be used. By default, the debug interface is SWD0 and this uses the same pin as port 0.14, therefore the initial conflict.
On the XMC2Go the debug interface is SWD1, so by configuring CPU_CTRL_XMC1 to use SWD1 the 0.14 pin can be used as an input.

The initial error message does not give too many details, would it be possible to highlight somehow in this case the hardware resources that create the conflict? Show Less

Hallo,
I've a short question to Dave3. Let's assume I have three IO004 apps (IO004/0, IO004/1, IO004/2, IO004/3) and i'm deleting IO004/2. Now, when I add another IO004 app, this one gets the instance number 4,
while instance number 2 remains unused. Is there any possibility to change app instances manually in Dave3?
Thanks for your answers!
Michael Show Less

Hi Guys,

I have a problem. My workspace is Dave 4.
My Xmc4400 demo board cannot connect to my PC when I want to debug.
Because the JLink has problem.
the Dave System gave me the MSG below.

But, I gave the power to the Xmc4400 demo board.
Could you give me any suggestion?
Thank you so much. Show Less

Hi All,

Happy new year.

I'm looking for a way to display how much program and data storage memory has been used after compiling in DAVE 3.

Thanks very much
Aaron Show Less