continuous watchdog resets with 1.6.4 IDE for ESP8266

[Hermann-SW]

Hi,

I can compile sketches and upload to ESP8266-01 without problems, but after cutting GND from GPIO0 and resetting my 3.3V UART2TTL connector [1] I see continuous watchdog resets for every sketch I tried.

The watchdog reset messages can be read in clear at 115200 line speed in IDE Serial Monitor. Therefore I intentionally did setup "my" serial connection at 9600, and added "delay(10)" to most simple sketch:

void setup() {
  delay(10);
  Serial.begin(9600);
}

void loop() {
  delay(10);
  Serial.println(millis());
}

Most times I do not get a single "millis()" output between 2 watchdog resets, but sometimes some outputs appear before next watchdog reset, see [2]. So the 2 questions I have are:

1. What can be a reason for the continuous watchdogs resets?
2. What can I do in sketch to avoid them?

Hermann.

[1]
http://www.aliexpress.com/item/FREE-SHIPPING-5sets-lot-CP2102-USB-2-0-to-UART-TTL-6PIN-Connector-Module-Serial-Converter/32256355230.html
[2]

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[GerryKeely]

Hi
There is no problem with the program.
I would suspect problem is electrical noise due to an insufficiently rated power supply or noise on the reset pin.Try a different power supply and/or place an electrolytic capacitor(100uF or higher) across the power supply as close as possible to the esp8266 .

Gerry

[Hermann-SW]

Thank you so much Gerry!

It was noise on reset pin, there are so many conflicting webpages stating which pins need to be connected and how, that I did not connect reset pin at all.

The little program runs for half an hour now without any issues (the small increase by 15 milliseconds instead of 10 in the middle seems to be related to other work done by ESP8266):

...
1801671
1801682
1801692
1801702
1801712
1801727
1801737
1801747
...

Just for completeness, these are the connections between my ESP8266-01 and CH340G USB2TTL capable for 3.3V and 5V.

ESP8266  USB2TTL (switch on 3.3V)
VCC      VC
RESET    VC
CH_PD    VC
TX       RXD
RX       TXD
GPIO0    [GND for flashing]
GPIO2    -
GND      GND

Never thought that wiring could be so easy without breadboard and working. Connect the open yellow cable (GPIO0) to GND (free pin on right connector), press reset on USB2TTL, compile and upload in IDE, open serial monitor and see program running (no disconnect of cable necessary at that point). Only if USB2TTL gets reset or disconnected, disconnect yellow GPIO0 cable from GND, and all is fine for "just running".

Hermann.