Arduino: Exception (28)

[svdgraaf]

I'm running into an issue, but I don't know where I can find the type of exception I'm getting:

Exception (28):
epc1=0x4000bf80 epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000000 depc=0x00000000

ctx: cont 
sp: 3fff1310 end: 3fff1540 offset: 01a0

>>>stack>>>
3fff14b0:  3fff1510 3ffe908c 3fff029c 402036f7  
3fff14c0:  3fff1510 0000002b 3ffe8f1e 3fff0518  
3fff14d0:  3fff1510 3ffe908c 3fff029c 40203b81  
3fff14e0:  3fffdad0 00000000 3fff029c 40203d08  
3fff14f0:  3ffe8d4d 00000000 3fff04e4 40203e65  
3fff1500:  3ffe8374 00000000 3fff04e4 40202284  
3fff1510:  3fff1ec0 27000000 3fff1e98 00000000  
3fff1520:  3fffdad0 00000000 3fff0511 40205d70  
3fff1530:  00000000 00000000 3fff0520 4010011c  
<<<stack<<<

 ets Jan  8 2013,rst cause:4, boot mode:(1,6)

wdt reset

 ets Jan  8 2013,rst cause:4, boot mode:(1,6)

wdt reset

I saw some issues mentioning memory usage, but I'm not sure if that's the case here.

Sketch uses 280,522 bytes (26%) of program storage space. Maximum is 1,044,464 bytes.
Global variables use 38,260 bytes (46%) of dynamic memory, leaving 43,660 bytes for local variables. Maximum is 81,920 bytes.

Can someone give me any pointers? Where could I find a list of the exceptions that there are? Where can I read some more? :)

[igrr]

Check out exception causes list and GDBStub library which may help you debug this issue.

Note: GDBStub got updated recently. I suggest trying the latest git version.

[svdgraaf]

Awesome, thanks! I'll take a look at it :)

[svdgraaf]

AWESOME! I learned so much from this :)

I ended up making a stupid mistake. For people getting the same problem later on, follow the steps above. Once you're in gdb, you can get a stacktrace by typing in backtrace in the gdb console.

[Testato]

@svdgraaf
may you tell whitch error you found ?
I have this message that is quite similar to yours

Exception (28):
epc1=0x402066e6 epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000004 depc=0x00000000

ctx: cont 
sp: 3ffeace0 end: 3ffeaeb0 offset: 01a0

>>>stack>>>
3ffeae80:  3fffdc20 3ffe9a68 3ffeaed4 40202a8e  
3ffeae90:  00000000 00000000 3ffeaed4 40201c0a  
3ffeaea0:  00000000 00000000 3ffe9e90 40100378  
<<<stack<<<

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

load 0x4010f000, len 1264, room 16 
tail 0
chksum 0x42
csum 0x42
~ld

[svdgraaf]

I had a loop somewhere where it shouldn't be ;) Just try to setup the debugger, you'll get a lot more information as a bonus :)

[HW-Siew]

Hi @svdgraaf , would you mind sharing how you get the gdb lib setup?

[svdgraaf]

@HW-Siew check out the description on the GDBStub page: https://github.com/esp8266/Arduino/tree/master/libraries/GDBStub

You have to include the library (download and put it somewhere in the Arduino path), run the included python tool (tcp_serial_redirect.py), leave it running, and connect to it with the nc command.

When the software on your esp crashes, exit the nc command (or leave it running, that's fine), and use the gdb command to connect to the error process.

You can get a backtrace on the gdb prompt, by doing backtrace, which would give you a backtrace of all the calls that were done, before running into the issue. There are a lot more options available in the gdb console, but the backtrace is all I needed to find my bug, I think you can get a list of all commands by running help.

[aliceand]

I'd like to use GDBSub but I'm using Arduino IDE with my ESP8266 on Windows 10. The GDBStub setup looks like it requires Linux. Is there a way I can use GDBStub with my Arduino IDE on Windows?

[Adsuarez]

Hi @aliceand, how could you solve your problem? i have de same problem :(

[Disane87]

Got the same too. I lt keeps crashing with Exception 28 bit only with an ESP8266. My ESP32 is working fine with the same code. This issue only exists with my private WiFi. At work its working like a charm.

It connects to WiFi and got an IP but than keeps crashing before the first http-call.

[d-a-v]

This is a closed issue. If you need help, follow the rule: read the doc (policy, troubleshooting) and:

Open a new issue with a minimal sketch reproducing the error.

[brianjmurrell]

Check out exception causes list and

That's a 404 now. Seems it's now https://github.com/esp8266/Arduino/blob/master/doc/exception_causes.rst.

[Leobute]

Go the same error. Reset the NodeMCU 8266-12E, It runs for 1 min more or less perfectly, then ….error.
Don't know what to do anymore.

Exception (28):
epc1=0x4020398b epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000000 depc=0x00000000

ctx: cont
sp: 3ffefd60 end: 3ffeff60 offset: 01a0

stack>>>
3ffeff00: 3ffeeca4 3ffeebf0 3ffeff20 3ffeebfc
3ffeff10: 3ffeeca4 3ffeebf0 3ffeec8c 4020254c
3ffeff20: 401070a0 b65a10ac 00000000 feefeffe
3ffeff30: 00000000 00000000 00000001 3ffeef30
3ffeff40: 3fffdad0 00000000 3ffeef28 40203d78
3ffeff50: feefeffe feefeffe 3ffeef40 40100710

[leifnel]

The command line for tcp_serial_redirect.py
./tcp_serial_redirect.py -p /dev/tty.SLAB_USBtoUART -b 115200 --spy -P 9980 --rts=0 --dtr=0

does not work with the one I found at https://github.com/pyserial/pyserial/blob/master/examples/tcp_serial_redirect.py

usage: tcp_serial_redirect.py [-h] [-q] [--develop] [--parity {N,E,O,S,M}] [--rtscts] [--xonxoff] [--rts RTS] [--dtr DTR] [-P LOCALPORT | -c HOST:PORT] SERIALPORT [BAUDRATE] tcp_serial_redirect.py: error: unrecognized arguments: -p -b 115200 --spy

Are there other like-named tcp_serial_redirect.py around?

---

Edit:
https://github.com/mapmeld/CrowdBot/blob/master/crowdbot-host/pyserial-2.6/examples/tcp_serial_redirect.py at least runs..

[sandevid]

How to fix this , i use nodeMCU

Error :
Exception (28):
epc1=0x4020a5d4 epc2=0x00000000 epc3=0x00000000 excvaddr=0x000001bb depc=0x00000000

stack>>>

ctx: cont
sp: 3ffffd90 end: 3fffffc0 offset: 01a0
3fffff30: 3fffdad0 00000000 3ffeed38 4020261b
3fffff40: 000001bb 3ffeed44 3ffe8884 3ffeeedc
3fffff50: 000001bb 3ffeed44 3ffe8884 40204a42
3fffff60: 40207ec0 dca79a95 3ffeed44 40203cbf
3fffff70: 3fffdad0 3ffeee10 3ffeed38 402057f0
3fffff80: 3fffdad0 3ffeee10 3ffeee64 402025d5
3fffff90: 40207ec0 552ba8c0 feefeffe feefeffe
3fffffa0: feefeffe 00000000 3ffeeeac 40207550
3fffffb0: feefeffe feefeffe 3ffe8558 40100a0d
<<

ets Jan 8 2013,rst cause:2, boot mode:(1,6)

ets Jan 8 2013,rst cause:4, boot mode:(1,6)

wdt reset

Source Code :

include

include

include

define LED 14 //D3

const char* ssid = "Telegram";
const char* password = "getupdate";
const char BotToken[] = "660345429:ACGlSKhCRMmgKHNJH4pG3ut_1R_66flenqQ";

WiFiClientSecure net_ssl;
TelegramBot bot (BotToken, net_ssl);

void setup() {
Serial.begin(115200);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
Serial.println(WiFi.localIP());

bot.begin();

pinMode(LED, OUTPUT);
}

void loop() {

message m = bot.getUpdates();

if (m.text.equals("on")){
digitalWrite(LED, HIGH);
bot.sendMessage(m.chat_id, "The Led 1 is now ON");

}else if (m.text.equals("off")){
digitalWrite(LED, LOW);
bot.sendMessage(m.chat_id, "The Led 1 is now OFF");
}
}`

Board : NodeMCU 1.0 (ESP-12E Module)
Upload Speed : 115200
Flash Size : 4M (no-SPIFFS)
Debug Port : Disabled
Debug level : None
IwIP Variant : v2 lower memoty
VTables : Flash
Exceptions : Disable
Erase Flash : Only Sketch
Port : COM4

Please help,
I have searched everywhere but there is no right solution

[10xnorellana]

i started the connection to wifi again before to use the http.begin(). it worked for me

[ethanlooney]

I am having the same issue as the above comments, has anyone been able to find a solution to this issue?