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Re: spi esp8266
Posted:
Wed Aug 16, 2017 4:38 pmby stern0m1
Gpio 15 on esp-12s is actually pulled down with a 12k resistor internally. see attached schematic of esp-12s
I tested with a multimeter without enabling spi it read 0 volts with enabling spi it read 3.3v
Re: spi esp8266
Posted:
Thu Aug 17, 2017 7:23 amby btidey
The internal pull up on GPIO15 is only operational during the boot period. After that it is controllable via the mode.
You may measure 0V with a 12K pull down but that is because the pull up has been de-activated by then.
The 12K may be sufficient for many modules but I think it is too high to give a good low during the boot phase. A low is supposed to be < 25% Vcc
Re: spi esp8266
Posted:
Thu Aug 17, 2017 7:54 amby stern0m1
Is there a way I can activate the internal pull up after boot up? So I could test.
Re: spi esp8266
Posted:
Thu Aug 17, 2017 9:13 amby btidey
pinMode(15, INPUT_PULLUP);