MOD-IO2: UEXT male vs UEXT female

[Peter G.]

Hello!

Are there any differences beetween UEXT male and UEXT female?

I cant see any, but

• the manual suggest it and
• it doesn't work the other way than mentioned in the manual

My sources:
https://www.olimex.com/Products/Modules/IO/MOD-IO2/resources/MOD-IO2.pdf
https://www.olimex.com/Products/Modules/IO/MOD-IO2/resources/MOD-IO2-Rev-B-schematic.pdf

The way it is working:
ESP32-EVB, UEXT male <-> UEXT female, MOD-IO2, UEXT male <-> UEXT cable <-> UEXT male, MOD-ENV
The way it fails:
ESP32-EVB, UEXT male <-> UEXT cable <-> UEXT male, MOD-IO2, UEXT female <-> UEXT male, MOD-ENV

Can someone please direct me to the right direction why there are differeneces?
Thanks in advance!

EDIT:
I'm sorry. I think it's an power supply issue. So I don't understand how UEXT should work exactly.
Each UEXT connector can provide power, but it has not to? Am I right?
So that's why in the manual is warned about closing that specfic jumpers?

(The only thing is: why it seemd to work? Strange, i2cscan seemd to work, but the values were wrong. But without correct power it's okay.  )

[Peter G.]

Sorry, it was my fault. I will answer my own question.

Each UEXT connector can provide power, but it has not to

That was the whole problem! Closing jumper UEXT_FPWR_E fixed it. So now following combination works like a charm:
ESP32-EVB, UEXT male 3V3 <-> UEXT cable 3V3 <-> UEXT male, MOD-IO2, UEXT_FPWR_E closed, UEXT female 3V3 <-> UEXT male, MOD-ENV

[LubOlimex]

Thanks for the update. Glad you figured it out. The thing with UEXT_PWR_E jumper was invented because by default "MOD-xxx" boards were not meant to provide power by default, because you usually connect them to "master" board that provides 3.3V and it is real possibility to have both "master" and "MOD-xxx" boards provide 3.3V at the UEXT, which would lead to short circuit.