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ESP-12 Garbage Characters via FTDI

PostPosted: Mon Aug 10, 2015 4:23 pm
by jotapeh
Hi to all, and apologies for starting what appears to be another very similar thread, however I cannot find my solution in the (several) pre-existing ones.

I recently received an ESP8266-12. My ESP is (as far as I can tell) correctly hooked up, with power supplied by a 4.5v charger that can provide 1.5A of current, voltage regulated by an LM317 to 3.3v and communications done via a level converter 3.3v-5v.

I have the same issue that many others have wherein upon bringing REST low temporarily, the 8266 will stream out a bunch of garbage characters in response. I am trying to communicate via the Serial Monitor provided by the Arduino IDE, which has worked well with other serial projects in the past. Here's the trouble:

1) No matter what baud rate I select, from 9600 to 115200, the text is always garbled
2) The ESP never responds to any TX from the FTDI, either via blinking LED or via reponse, regardless of what I send (usually "AT\r\n" and variants)

EDIT: UPDATE - after doing more digging on this specific module I learned that sometimes the baud rate is an unconvential 74880bps, so I added that baud rate in. Now I get this message:

Code: Select all ets Jan  8 2013,rst cause:2, boot mode:(7,7)

waiting for host


But the device still refuses to respond to any TX activity regardless.

I have carefully inspected the TX/RX solder joints and checked connectivity with a multimeter but it all looks okay. I am a bit stumped right now where to go from here. The device definitely seems operational, but this is quite frustrating..

Re: ESP-12 Garbage Characters via FTDI

PostPosted: Mon Aug 10, 2015 4:52 pm
by PaulRB
jotapeh wrote:... the baud rate is an unconvential 74880bps, so I added that baud rate in.


Hi, I am in a similar position with my ESP-01. I too am very frustrated, because I have had the board working well recently, but suddenly it refuses to run Arduino sketches, even though the upload process seems to be OK.

How did you add the 74880 baud rate? What files did you update?

thanks,

Paul

Re: ESP-12 Garbage Characters via FTDI

PostPosted: Mon Aug 10, 2015 7:09 pm
by martinayotte
For the 74880bps message at boot up, this is normal.
Unfortunetely, not all USB-TTLSerial provide functionality with this baud rate available. But it is not mandatory to have, except to decrypt the problem. Here it seems that jotapeh has a good one.

@jotapeh, for the booting issue, did you keep the stock firmware already present on your module or did you got change to upload some other one ?

@PaulRB, since you've already got your module working with ArduinoIDE upload, do you remember what was different when problem occured ? How did you connect GPIO15/GPIO2/GPIO0 ? Do you have pulldown on GPIO15 and pullups on GPIO2/GPIO0 ? What about special other pins, ie : CH_PD and RES, Do you have pullops there too ?

Re: ESP-12 Garbage Characters via FTDI

PostPosted: Mon Aug 10, 2015 11:20 pm
by jotapeh
@martinayotte thanks for the speedy reply. I am trying to use the unit with the stock firmware that shipped. My ultimate purpose is to simply use it as a wifi bridge for an arduino, but at the moment would be satisfied with simply seeing some decipherable responses :)

@PaulRB I switched to using CoolTerm, which is freeware and can use custom baud rates supplied by a baudrates.ini file.