ESP8266 Community Forum

- Fri Jan 08, 2016 1:56 pm #38223 I have spent several hours now Googling around and trying different things, but I can't seem to find anything that works, so here goes:

I have a LoLin Nodemcu V3, ie. it's just basically a Nodemcu V1.0, but with the reserved - pins changed into +5VOUT/GND. I have a Nokia 5110 LCD connected to HSPI - pins and it works wonderfully until I toggle GPIO9 -- at this point the display goes haywire. I have no idea why, there is nothing actually physically even connected to GPIO9, the Internets says that I should be able to use GPIO9 and GPIO10 on a Nodemcu just fine without any modifications as long as I am using DIO - mode for the internal Flash (and I am, not QIO). I have also tried adding both

Code: Select allPIN_FUNC_SELECT(PERIPHS_IO_MUX_SD_DATA2_U, FUNC_GPIO9);
pinMode(9, FUNCTION_3);


to my sketch, but they do diddly squat.

Can anyone shed any light on this?

- Sat Apr 02, 2016 10:09 am #44679 I suspect the issues here are the dedicated traces to the flash chip under the can.
The traces are set up for QIO flashing and dedicate GPIO9 and GPIO10 to that purpose.
GPIO9 and GPIO10 are connected to pins 3 and 7 of the flash chip.
If pins 3 and7 are lifted and both wired to 3.3v via a very small jumper wire then flash chip will still flash under DIO and since pins 3 and 7 are lifted they free up GPIO9 and GPIO10 so FUNCTION_3 will work in assigning then to GPIO