Uno R4 Wifi freezing...

[leosoftGR]

Hello all,

I am using an Uno R4 wifi as a websockets server and I am experienced a strange issue. Whenever I reload my webpage (...containing javascript websockets client) or whenever I try to connect a second client to my arduino, this completely freezing. I thought it might be a memory issue and I tried to create an empty project for testing but same results. Of course I am using the latest 0.4.1 firmware.
Another test i did, was to install a websockets client tester plugin to chrome so, I could try to connect directly from my browser without using my buildin webpage but still the same.
Also tried to reduce the WEBSOCKETS_MAX_DATA_SIZE from webshocket.h as an experiment but still no luck.

Any ideas??????

[leosoftGR]

According to this thread :

#877

I decided to remove experimentally some small delays of 10ms that I had in my loop, and notice big improvement. I may still not be able to connect two clients at the same time, but at least the first one seems to be stable. I can even reload the page without freezing my box. And if I close it first, then I am able to re open it. With a few words, the first connected client works fine. (...at the moment)

Thanks to @furdog

[leosoftGR]

And according the latest reply from Markus @Links2004 regarding the reasons to avoid a delay, i would like to ask Markus if a heavy loop (from calculations or serving multiple web pages or even too many serial.prints) could have the same luck with delay command or not

Thanks for your time

[Links2004]

yes any think that takes a long time can have the same affect, a delay is a do nothing for x.
it makes no difference if you replace do nothing with do math ;)

what may help is to make sure that all open messages a handled before you do the heavy calculations.
by calling the loop function multiple times.

a other option is to place the heavy calculations in a dedicated thread.
some ESP32 for example have 2 cores which allows parallel execution (see xTaskCreatePinnedToCore).
but not sure what the R4 Wifi is capable of.

[leosoftGR]

Parallel execution attached on a core was my fist thought but unfortunately its not available on UNO R4.

What I've noticed also is that a weak WiFi signal can also cause the same issue. In other words, if you want to have a flawlessly working websocket server, you need to keep your box as much free as possible.

Btw, something else that it maybe important... I tried to reduce WEBSOCKETS_SERVER_CLIENT_MAX from 5 to 1 and prevent my setup from crashes etc, but after compilation my Uno r4 is freezing while entering to main loop.

[Links2004]

have you enabled the debug output of the websocket lib?
this sounds more and more like there is a TCP / Network stack problem on the UNO R4.

if the R4 has printf support then its as easy as setting the DEBUG_ESP_PORT define to for example Serial1

arduinoWebSockets/src/WebSockets.h

Lines 46 to 51 in 7a4c416

	#ifdef DEBUG_ESP_PORT
	#define DEBUG_WEBSOCKETS(...) \
	{ \
	DEBUG_ESP_PORT.printf(__VA_ARGS__); \
	DEBUG_ESP_PORT.flush(); \
	}

if this not the case then a custom function can be called via defining DEBUG_WEBSOCKETS

[leosoftGR]

Unfortunately there is no printf for serial on UNO R4 :(

[Links2004]

ok that makes it a bit harder to see whats going on, but may try:

 #define DEBUG_WEBSOCKETS(msg)               \ 
     {                                       \ 
         Serial1.print(msg); \ 
         Serial1.flush();             \ 
     } 

with that we can at least get a idea where in the code the problem is, no details of what happening but by searching the msg in the code we can at least get a hint.

[leosoftGR]

You mean the issue regarding the weak signal or regarding WEBSOCKETS_SERVER_CLIENT_MAX ?

[Links2004]

we can look at both, but make sure to clearly label the logs and conversation.

[leosoftGR]

Its sounds maybe stupid question but since now I am using the Arduino Cloud Editor how can I set there a compiler debug switch ?

[Links2004]

good question, have never used it.
if you can edit the lib files then it my is easier to simply add the define to the WebSockets.h

[leosoftGR]

I will put WebSockets.h and WebSocketsServer.h inside my project so I will be able to edit the defines. Like this:

`#include "WebSocketsVersion.h"
#define DEBUG_WEBSOCKETS

#ifndef NODEBUG_WEBSOCKETS
#ifdef DEBUG_ESP_PORT
#define DEBUG_WEBSOCKETS(msg) \
{ \
Serial.print(msg); \
Serial.flush(); \
}
#else
// #define DEBUG_WEBSOCKETS(...) os_printf( VA_ARGS )
#endif
#endif

#ifndef DEBUG_WEBSOCKETS
#define DEBUG_WEBSOCKETS(...)
#ifndef NODEBUG_WEBSOCKETS
#define NODEBUG_WEBSOCKETS
#endif
#endif
`
But after compilation and uploading, no debug message coming on Serial from the library :(

[Links2004]

my bad, try:

   #define DEBUG_WEBSOCKETS(msg, ...)               \ 
     {                                       \ 
         Serial1.print(msg); \ 
         Serial1.flush();             \ 
     } 

[kakopappa]

Unfortunately there's no printf in ArduinoCore-renesas. When i was working on R4 this is what I did to see the debug messages in the Arduino Serial Monitor.

#include <stdarg.h> // Required for va_list, va_start, va_end

.......

size_t va_printf(const char *format, ...) {
  va_list arg;
  va_start(arg, format);
  size_t ret = vprintf(format, arg);
  va_end(arg);
  return ret;
}

#define DEBUG_WEBSOCKETS(...) va_printf( VA_ARGS )

[furdog]

I will put WebSockets.h and WebSocketsServer.h inside my project so I will be able to edit the defines. Like this:

There so many things that could go wrong here.

• First at all make sure you put defines before your header files included.
• Make sure other c/cpp files ALSO include them.
• Make sure you include files you added inside your project and not the default library. Better remove default library, so you definitely could see if arduino uses correct files.

If you use heavy computing that blocks other tasks for excessive amount of time, i would recomend you to use some kind of coroutines, duff devices, computed gotos, callbacks, or state machines, or just plain conditionals. It takes some effort to implement, but in single threaded applications it's always good to split monolith tasks into smaller ones, so they work very limited ammount of time.

for example:

void loop() {
  //calculation-heavy routine, takes a lot of time to execute
  for (int i = 0; i < 100000; i++) {
      some_sum += some_calculation();
  }
  
  //do something with some_sum...
  
  ...
  
  //other tasks
  
  ...
}

This "for" loop will take huge amount of time to execute, so its better to rewrite it like this:

void loop() {
  static int i = 0;
  
  //Just a simple conditional which takes almost no time to evaluate
  if (i < 100000) {
      some_sum += some_calculation();
      i++;
  } else {
    //do something with some_sum..
    ...
    
    i = 0;
  }
  
  //other tasks
  
  ...
}

These are only examples how to write efficient code on single-threaded devices.