[SOLVED] ESP8266 fails to boot with NRF24L01+ connected

[Daanoz]

Got it solved!

Ok, after debugging for a while: the problem is with the CSN pin on GPIO pin 15. Pin 15 is also used in the ESP8266 to define boot from SD card. Somehow, at least in my case, after a reset, the NRF chip sets the CSN pin to high (measured it with a multimeter), causing the ESP8266 to start the SD-card procedure, which fails of course. The solution for me is swapping the pins for inclusion with the CSN pin:

So:
CSN -> GPIO 5 -> D1
Inclusion mode -> GPIO 15 -> D78

One question though: I also seem to have SPI pins on the other side of the Devkit, why aren't those used?

[hek]

https://github.com/mysensors/Arduino/issues/408

[Daanoz]

Ok, another small update from my side. I think I localized the root cause of what was putting my CSN in a high state.

Last couple of days I was testing with a sensor connected with power through a FTDI adapter, the adapter had a nice switch to chose between 3.3v and 5v. The sensor was actually having a problem, this problem to be precise, the sensor fails after a couple of hours. At first I didn't think much about it, since the switch was on 3.3v. After having 2 NRF chips failing, I measured the output of the 3.3v pin on the arduino pro mini, you guessed it: 5V! :sob:

The funny thing is, the first chip that failed, I used on the gateway to test if it was working, because it did work without a reset, I didn't think much about it. Now I know that the 5V Probaly fried something in the chip, causing to output high on the CSN in some cases...

Attached a photo of the second chip that fried even more (the right one with the 2 black blobs below the chip). Anyway, thanks for the help folks, finally can start building something!

[hek]

Ok, thanks for the update on your issue.

[barduino]

@Daanoz,

Inland FTDI?

I have the same with one of those.

[Ironbar]

I also had one that would not change from 5v to 3.3v. I don't remember which brand it was but it had a switch instead of a jumper. It took me a long time to figure out that it was the problem.

[Daanoz]

It's not really a brand... It's this one: http://www.aliexpress.com/item/FT232RL-3-3V-5-5V-FTDI-USB-to-TTL-Serial-Adapter-Module-For-Arduino-TE321/32574619454.html

[Ironbar]

That's the one.

[Yveaux]

The switch most likely has only to do with logic levels of the data lines. It is not related to the power output. Very confusing indeed (another Chinese fail if you ask me)

[barduino]

I have this one, looks the same...