[Solved] ESP8266 12E keeps rebooting (rst cause:2, boot mode:(3,6))

[Khorne13]

Hello,
I want to use my ESP8266 12E with a keypad, I wired it this way:
1-----D0
2-----Rx
3-----SD3
4-----D3
5-----D4
6-----D5
7-----D6
8-----D7

I didn't use the D1 and D2 because I want to add an LCD I2C later.

Well, first I tried this code, same wiring it works perfectly:

#include <Keypad.h>
 
const byte n_rows = 4;
const byte n_cols = 4;
 
char keys[n_rows][n_cols] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
 
byte colPins[n_rows] = {D3, 10, 03, D0};
byte rowPins[n_cols] = {D7, D6, D5, D4};
 
Keypad myKeypad = Keypad( makeKeymap(keys), rowPins, colPins, n_rows, n_cols); 
 
void setup(){
  Serial.begin(115200);
}
 
void loop(){
  char myKey = myKeypad.getKey();
 
  if (myKey != NULL){
    Serial.print("Key pressed: ");
    Serial.println(myKey);
  }
}

But later in my project I will need to use another commands and somethings, so I used this one, very similar

`#include <Keypad.h>
 
const byte n_rows = 4;
const byte n_cols = 4;
 
char keys[n_rows][n_cols] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
 
byte colPins[n_rows] = {D3, 10, 03, D0};
byte rowPins[n_cols] = {D7, D6, D5, D4};
 
Keypad myKeypad = Keypad( makeKeymap(keys), rowPins, colPins, n_rows, n_cols); 
 
void setup(){
  Serial.begin(115200);
}
 
void loop(){
           char keypressed = myKeypad.waitForKey();
         if (keypressed != NO_KEY)
             {
             char c1 = keypressed;
              Serial.println(c1);
              }
}

But when I upload this on the board, the board starts rebooting, and I get this in the serial monitor

ets Jan 8 2013,rst cause:2, boot mode:(3,6)

load 0x4010f000, len 1384, room 16
tail 8
chksum 0x2d
csum 0x2d
v09f0c112
~ld

I'm powering it from my computer, and as you can see all I did is changing a function and add a variable
Thanks

[Khorne13]

Same wiring same all, the problem starts if I change the function "getkey" to "waitForKey" I don't know why, the function waitForKey stops the program and wait until a key is pressed, not like "getkey" that keeps the programme looping

[RudyFiero]

Include a delay in the routine. That would allow background tasks that need to run. You can not have long blocking code with the ESP8266. It will cause the behavior you see.

[Khorne13]

Yes I noticed if I keep pressing buttons from the keypad the board doesn't reboot until I stop for few seconds.
Is there a way to increase that rebooting perdiod, like from 2seconds to 10 or more seconds, it would be great for me if it waited few seconds more before rebooting?
Thanks

[WheresWally]

If you load the original sketch, is all ok then?

reset causes:
    0: 
    1: normal boot
    2: reset pin
    3: software reset
    4: watchdog reset

boot device:
    0:
    1: ram
    3: flash - See more at: http://www.esp8266.com/viewtopic.php?p=2096#p2112

[igrr]

Pin 10 is used to connect flash memory inside the esp12 module, I doubt it can be used for other purposes.

[Khorne13]

As you can see I kept the same wiring, even if I used the pin 10, the first code works fine but the second one keeps rebooting if I don't press buttons quickly, the problem appears if I change the function I mentionned above.

I've read about a reset period that can be modified, but I don't have further information about it. If you know please tell me, thanks.

[igrr]

Ok, sorry, missed that part.

Keypad::waitForKey method in Keypad library is not compatible with the ESP8266 Arduino core because it uses a busy loop. This part of the code library needs to be modified, by inserting a delay(0); or yield();:
https://github.com/Chris--A/Keypad/blob/master/src/Keypad.cpp#L211-L215

[Khorne13]

Oh, I'm a beginner, I didn't understand what you meant...
Should I remove the keypad "waitforkey" function, or should I modify something to be able to use it?
Thanks

[WheresWally]

The codes are :

0 -> normal startup by power on
1 -> hardware watch dog reset
2 -> software watch dog reset (From an exception)
3 -> software watch dog reset system_restart (Possibly unfed watchdog got angry)
4 -> soft restart (Possibly with a restart command)
5 -> wake up from deep-sleep
Looking at the provided code you can decide from what reason the chip is restarting.

I found that loops need a yield() to be ESP8266 friendly, to feed the watchdog before it triggers.
the line referred to by Igrr ...
while( (waitKey = getKey()) == NO_KEY ); // Block everything while waiting for a keypress.
most likely should be ...
while( (waitKey = getKey()) == NO_KEY ) yield(); // Block everything while waiting for a keypress.

[igrr]

Or rather,

while( (waitKey = getKey()) == NO_KEY ) yield(); // DON'T block everything while waiting for a keypress.

:)

[Khorne13]

If it doesn't block the program, it would be like the function getKey() and this one make a little mess in my program, I really want the program to wait like 5s or more in this step before looping again.

I want the program to wait a key then store it into a char c1, then wait another key and store it into char c2 ... So I can do other things later. If I use the function "getkey" it mess with my program: I can only store one char, because the program doesn't wait. (to explain my little idea).

And how can I modify the library if I want to test your solution.

Thanks guys.

[Khorne13]

I downloaded that library by using the "library manager" method, where can I find the cpp file so I can modify it?
Thanks

[lights0123]

It is in the folder under your sketchbook location, so probably Documents/Arduino/libraries/Keypad/Keypad.cpp.

[Khorne13]

No didn't find it there.
I have found that library on the arduino library "Program files - Arduino - Libraries"
Because I tried first time with an Arduino UNO, then when I used the NodeMcu I had that library problem and I downloaded it using the library manager.
"I don't know if both uses the same library, or the NodeMcu ones are saved in another place like wifi libraries ..."

[Khorne13]

Hello everyone,
So it seems it works fine,
For everyone having the same problem: I did a copy of the library (so not to ruin it), then I opened the file keypad.cpp with note++, I did the modification proposed by "WheresWally" and "igrr", then I saved the .cpp file as Keypad2 and renamed the keypad.h to keypad2.h, then I kept the same second code mentionned above, now I can store 2 keys as c1 and c2 and manipulate them with using the modified version of "waitForKey" function.

You guys thanks so much you're really helpful.