# Bindings Gpio cf3GpioControl

**URL:** <https://mangoh.discourse.group/t/bindings-gpio-cf3gpiocontrol/1740>\
**Category:** mangOH Red\
**Created:** [July 19, 2018, 10:20am UTC](https://mangoh.discourse.group/t/bindings-gpio-cf3gpiocontrol/1740 "2018-07-19T10:20:05Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Louis96](https://avatars.discourse-cdn.com/v4/letter/l/4da419/32.png) [@Louis96](https://mangoh.discourse.group/u/Louis96)\
**Post date:** [July 19, 2018, 10:20am UTC](https://mangoh.discourse.group/t/bindings-gpio-cf3gpiocontrol/1740/1 "2018-07-19T10:20:05Z")

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Hello,

I tried to understand how works gpio library by testing the tuto “cf3GpioControl”.

> **[mangOH/mangOH](https://github.com/mangOH/mangOH/tree/master/samples/tutorials/mangOH_Red/gpio/Cf3GpioControl)**
>
> Primary mangOH git repository. Contribute to mangOH/mangOH development by creating an account on GitHub.

But it was not working and I noticed 3 incoherences :

- the command LE\_INFO() did not write anything in the log
- on the mangOH red schematics, the wp Pin7 is not connected, and the gpio7 (pin40) is unreachable (port IoT). So what means the label “le\_gpioPin7” mentioned in the bindings section ?
- on the mangOH red schematics, the wp Pin4 is connected to the UART1, the gpioExpPin4 match with alim VCC1, and the gpio4 from the gpio Expender pin 4 is linked to the RPI port (not to a LED). So what means the label “mangoh\_gpioExpPin4” mentioned in the bindings section and aimed to drive a led ?

Finally, I tried to change the pins to use the generic push button (gpio 34 of the module WP7702 pin 100) to control the D410 LED ( gpio 14 of the module WP pin 21) of the mangOH red.

But I’m not able to use them: I have error message “Operation not permitted” when launching the app.  
So I’m still wondering how to use pins with gpioService  
Can you help me ?

Thank in advance  
Regards  
Louis