GPIO2 behavior on bootup


GPIO2 behavior on bootup

Postby rith87 » Thu Apr 28, 2016 9:22 pm

After about 58 ms, I see the following waveform on GPIO2 (verified with a scope that they are pulses, not sinusoids). Is this expected? Or am I doing something crazy?



Re: GPIO2 behavior on bootup

Postby rith87 » Fri Apr 29, 2016 3:11 pm

Well, figured it out. So GPIO2 was acting as UART TX at 74880:

' 'ets' 'Jan' '' '8' '2013,rst' 'cause:2,' 'boot' 'mode:(3,6)

load' '0x40100000,' 'len' '1612,' 'room' '16' '
tail' '12
chksum' '0xb1
ho' '0' 'tail' '12' 'room' '4
load' '0x3ffe8000,' 'len' '672,' 'room' '12' '
tail' '4
chksum' '0xbf
csum' '0xbf

rBoot' 'v10201' '-' 'richardaburton@gmail0com
Flash' 'Size:' '' '' '8' 'Mbit
Flash' 'Mode:' '' '' 'QIO
Flash' 'Speed:' '' '40' 'MHz

Booting' 'rom' '00\r\n'0' (framing error)

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Joined: Mon Oct 27, 2014 10:40 am

Re: GPIO2 behavior on bootup

Postby Espressif_Kelly » Fri Apr 29, 2016 3:33 pm


Yes, GPIO2 can function as U1TXD.
More informations about pin definitions about ESP8266EX, you can refer to "0D-ESP8266__Pin_List__Release_15-11-2014.xlsx" which can be obtained in the following link.


More questions, please feel free to let us know.


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