ESP8266 Community Forum

- Thu Jul 16, 2015 8:51 am #23425 Hi, I'm new here and to the platform.

I purchased this dev board so I could code "on the go".

I've flashed various firmwares to the system, and I have been having a lot of trouble.

When it boots, at 115k baud I get:

Code: Select allwdt reset
load 0x40100000, len 29824, room 16
tail 0
chksum 0x0b
load 0x3ffe8000, len 3064, room 8
tail 0
chksum 0xc3
load 0x3ffe8bf8, len 8, room 8
tail 0
chksum 0xa5
csum 0xa5
{l�

If I switch over to 9600 baud, I get this:

Code: Select allCommunication with MCU...
.Got answer! AutoDetect firmware...

Can't autodetect firmware, because proper answer not received.
ÖÔô(ý@H

Then, sometimes, if I'm holding the board in my hand and it is not on the table, I get this:

Code: Select allNodeMCU 0.9.6 build 20150704  powered by Lua 5.1.4
lua: cannot open init.lua
> =node.heap()
35184
> =node.heap()
35184
> ?)DêŠâD

I am able to send a few commands, like node.heap(), and then it resets again, typically after about 2 commands (or 2 seconds, whichever comes first).

My question is...

Am I having a power deficiency issue here? I may hack in a 'dual usb' cable for power and see if that helps.

I find it strange that the system boots if I hold it in my hand. That seems like a grounding issue or floating reset pin. I can't manage to find the documentation on running the bare minimum on this board, am I omitting something silly like pulling the reset pin low or something?

I know there is a basic wiring setup that is needed, but I assumed the NodeMCU dev board would handle these bare minimum pin connections onboard.

Thank you.

- Thu Jul 16, 2015 2:14 pm #23450 I have the same issue. The EPS-12 keeps resetting. I'm assuming it's a lack of power or anything else. I use a modified powerbank as power source. Added a 3.3v regulator and a capacitor to try to keep the output at steady as possible.

I just came accross the following (blog)post http://internetofhomethings.com/homethings/?p=396

The post contains a list of items you can check that can result in resets. As I assumed, the powersource is one item on his list. It also contains some solutions about adding some extra capacitors between VCC and ground. I've not really tried this point, only in my powerbank.

It also states that the ESP8266 is not really friendly with a breadboard. That's what I'm going to try, remove the ESP12 from the breadboard and connect directly.

- Fri Jul 17, 2015 11:53 am #23513 Thanks for the link, it has some really good suggestions to try. It sounds like a pretty common problem.

I'll report back if power ends up being the issue.... That would be disappointing since the board seems like it should be set up properly to run off USB, but I guess it could be my computer not supplying the proper current. I'll try putting a big cap on there as well to see if a current spike is causing a brownout.

- Sat Jul 18, 2015 5:42 am #23546 Heya,

I have also NodeMCU 0.9 dev board and yes it needs stable USB power, at least 4.6V, mine worked all the way down to 4.4V but below that it's very flaky ..
Connected to good selfpowered USB hub I've never had any problems with this board (that includes driving TFT and 4 I2C).

--
Mozz