ESP8266 Community Forum

- Sun May 24, 2015 11:46 am #18318 I'm attempting to get a very simple blink example running on an ESP12 (ESP8266MOD). Unfortunately, when running the code I get Fatal Exception errors.

Am I doing something wrong, or is the ESP12 faulty?

Code and error message below.
I'm using an FTDI connector, and pin setup may be found below.

Some other observations:

With GPIO0 low, I'm able to successfully upload programs to the ESP from the Arduino. And I have successfully loaded NodeMCU.
The ESP doesn't appear to boot successfully in Flash Boot mode (GPIO0 pull-up). I get garbage no matter what baud I try (including 74880). I can only get output when GPIO0 is low (UART Download mode) after a fresh power cycle and with "esptool.py run".
I loaded a larger arduino program to the ESP12 and got checksum errors. Happy to post more detail regarding this if useful.

Pins:

A switch from GPIO0 to ground (with a pull-up resistor to VCC)
GPIO2 and CH_PD connected to VCC
GPIO15 connected to ground
VCC and ground to a breadboard power supply at 3.3v
FTDI Adapter RX, TX to ESP12's TX, RX respectively. FTDI ground to ground.

ESP Arduino code:

Code: Select allvoid setup() {
  // initialize digital pin 13 as an output.
  pinMode(5, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(5, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);              // wait for a second
  digitalWrite(5, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);              // wait for a second
}

Output from

Code: Select all./esptool.py --port /dev/ttyUSB1 run && picocom /dev/ttyUSB1 -b 115200 --omap crcrlf

Code: Select allTerminal ready
load 0x40100000, len 28688, room 16
tail 0
chksum 0xb2
load 0x3ffe8000, len 1316, room 8
tail 12
chksum 0x65
ho 0 tail 12 room 4
load 0x3ffe8530, len 1500, room 12
tail 0
chksum 0x61
csum 0x61
Fatal exception (3):
epc1=0x40221132, epc2=0x00000000, epc3=0x00000000, excvaddr=0x401002b1, depc=0x00000000
Fatal exception (3):
epc1=0x40212435, epc2=0x00000000, epc3=0x00000000, excvaddr=0x401003c4, depc=0x00000000
Fatal exception (3):
epc1=0x40212435, epc2=0x00000000, epc3=0x00000000, excvaddr=0x401003c4, depc=0x00000000
Fatal exception (3):
epc1=0x40212435, epc2=0x00000000, epc3=0x00000000, excvaddr=0x401003c4, depc=0x00000000
Fatal exception (3):
epc1=0x40212435, epc2=0x00000000, epc3=0x00000000, excvaddr=0x401003c4, depc=0x00000000
Fatal exception (3):

- Mon May 25, 2015 8:50 am #18397 I don't see anything wrong with what you are doing. Have you tried running another example or did you test the stock AT firmware before you ran these tests?

In my limited testing I've found my ESP-12 modules to much more unstable than my ESP-07 modules. I unsoldered the RF shield on one of my ESP-12 modules and wrote about my findings in the hardware forum.

Just as a test I might try a different power supply if you have one.

- Mon May 25, 2015 9:49 am #18402 Thanks, George. I did play with the AT interface prior to flashing nodemcu. Appeared stable enough.

I've found nodemcu relatively stable but am not enjoying the memory limitations. I'll give another power supply a go and see where I get to.

- Tue Jun 02, 2015 11:24 pm #19300 hi,
Are you powering the module from the ftdi board?
if so i think that's likley to be your issue.
Either try using a meatier power supply to provide vcc to the module (use a common ground to your ftdi)
or, and this might work it might not, grab a capacitor and put it accross the vcc and ground of the module to smooth out the power draw. i'm using a 2200uf but that's much bigger than what you need.