ESP8266 Community Forum

So I got an order of a few of the ESP-12 modules after liking the 03's and the 01's, and I'm having an interesting problem. I can use the AT firmware, but whenever I pull GPIO0 to ground with a resistor to program (before power up of course) it refuses to be programmed. I got out my logic analyzer and for some reason it is outputting a steady 2MHz signal on GPIO0. Has anyone had this happen before?

EDIT:

Just to add some more information, when it boots in to the AT software, here is the output at 76800 baud:



And here is when GPIO0 is pulled down:



Also, looks like the 2MHz figure is just as high as my cheap logic analyzer can measure, looks like it might be the 26MHz clock,

What value of a resistor are you using to pull GPIO 0 low for flashing? I use a 10K. Also, to flash, GPIO 2 must also be pulled high.

Think of the three pins GPIO15, GPIO 0 and GPIO 2 as forming a 3 bit binary number. When then have the value "001", the ESP8266 is in programming mode. When they have the value "011" the device will boot from flash.

For some reason it started working when I changed the uploader to DIO flash instead of QIO flash. Also have there been issues with some of them having GPIO 4 and 5 switched? Mine are flip flopped from all the pinouts on the web

kolban wrote:What value of a resistor are you using to pull GPIO 0 low for flashing? I use a 10K. Also, to flash, GPIO 2 must also be pulled high. I don't use a resistor at all without problems as yet although you don'tlike that. I think you mean GPIO2 must be high to run in FLASH mode

Think of the three pins GPIO15, GPIO 0 and GPIO 2 as forming a 3 bit binary number. When then have the value "001", the ESP8266 is in programming mode. When they have the value "011" the device will boot from flash.
I didn't initially understand that Thanks, trying to bring it together clearer in my head. 15,and 0 need to be low for UART mode , 15 low and 0 high for FLASH(running) mode.

So ematson5897 I would say you are getting into UART mode to upload the hex to the chip when GPIO0 is pulled low and on my ESP-12's it gives just one blue flash as it powers up and waits.

ets Jan 8 2013,rst cause:1, boot mode:(3,7)

So 3=011 or FLASH(running)mode

ets Jan 8 2013,rst cause:1, boot mode:(1,7)

So 1=001 or UART mode