use maximum GPIOs / activate Dx-Pins as GPIO(Output)

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Re: use maximum GPIOs / activate Dx-Pins as GPIO(Output)

By Duane J
- Sat Jul 18, 2015 10:20 am #23562
The problem is, most of those are used for the flash chip on the ESP, as in you'll crash the ESP8266 if you fiddle with the wrong GPIO.

Note that it IS possible to reduce the flash chip to dual IO mode, freeing up a few of those pins for use as GPIO.


I think I've done this already, and didn't realize it. For instance, I was trying to set the pinMode of GPIO9 to OUTPUT (without the knowledge of PIN_FUNC_SELECT), and the esp8266 kept resetting. I couldn't see what I was doing wrong :)

So, how DO you "free up a few of those pins for use as GPIO" in such a way as to not crash the mcu? Your comment seems to suggest PIN_FUNC_SELECT isn't enough?

Also, one last question: Is it possible to use these extra pins on the esp-12e for SPI communication to an external device? I've noted in several images of the esp-12e that the pins appear to be labeled with SPI-like pin names. For instance: https://esp8266hints.files.wordpress.co ... p-12e1.jpg Would SPI mode interfere with flashing?
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Re: use maximum GPIOs / activate Dx-Pins as GPIO(Output)

By h4rm0n1c
- Sat Jul 18, 2015 10:44 am #23570 It took me a little while to find it (I spend a LOT of time looking up ESP related info, there's lots of people posting blogs about things they've done with it, very useful to learn from), but this outlines the work required to free up GPIO9 and 10.

http://smarpl.com/content/esp8266-esp-2 ... and-gpio10

As you can see, it is somewhat in depth and a little bit fiddly, you'll also need to make sure you always select DIO mode for the flash, QIO will obviously not be available once this mod is made.
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