Pin has not been exported for write

[antsmo]

Hi, I've just started using rpi-gpio and wanted to try out the functions. I'm trying to write to a pin (7) but I'm getting the following error:

Pin has not been exported for write

Node: v6.3.0 Raspbian: 8.0 Jessie

If the project is still active, any advice would be great. Thanks.

[julienvincent]

Hi, could you please share some of your code so as to make it easier to see where things are going wrong.

[antsmo]

Damn yeah sorry. I'm away from the computer at the moment but I just copied the example code.

[kirgy]

Same issue, using copy-paste example code on Raspbian, Pi Zero. Have also tested on Raspberry Pi v1:

var gpio = require('rpi-gpio');

gpio.setup(7, gpio.DIR_OUT, write);

function write() {
    gpio.write(7, true, function(err) {
        if (err) throw err;
        console.log('Written to pin');
    });
}

pi@raspberrypi:~/test $ node -v
v4.2.1

[ghost]

I am having the same issue, details:

• raspberry pi 2 b
• nodejs v6.2.2
• npm v3.9.5

Code:

    var gpio = require('rpi-gpio');                        
    var pin = 25;                                          

    gpio.setup(pin, gpio.DIR_OUT, writeToPin);             

    function writeToPin(){                                 

        gpio.write(pin, true, function(err){           

            console.log(err);                      

        });                                            
     }                                                      

Error:

    raspberrypi ~/nodegpio $ npm start

    > nodegpio@1.0.0 start /home/pi/nodegpio
    > sudo node index.js

    Error: Pin has not been exported for write    at /home/pi/nodegpio/node_modules/rpi-gpio/rpi- gpio.js:227:20
    at _combinedTickCallback (internal/process/next_tick.js:67:7)
    at process._tickCallback (internal/process/next_tick.js:98:9)

I checked the rpi-gpio code and it looks like the gpio legend in the code for raspberry pi v2 has pin 25 as ground but my board has it as gpio pin.

[JamesBarwell]

I think that these may be the same issue as was reported and solved in #41. I suspect an error is being thrown after setup and is not being handled here. The error may well be due to a lack of root permission when running the script. Could you try running again using sudo, and if that fails then ensure you are catching errors after setup?

  gpio.setup(pin, gpio.DIR_OUT, writeToPin);             

    function writeToPin(err){  
      if (err) throw err;

      gpio.write(pin, true, function(err){

[mxyue]

Error: Pin has not been exported for write

maybe you need start program with root or sudo permission like sudo npm start

[miopa]

I had the same problem. It turned out - I was writing to a pin that can't be used for writing. The confusion originates in the different pin numbering schemes. The library uses WiringPi as default scheme, while most of the references online use the BCM naming.

Here you can find both schemes referenced: http://ocw.cs.pub.ro/courses/iot/labs/04

[yunw]

I resolved this issue after applying both fix from @miopa and @JamesBarwell

[JamesBarwell]

Glad you got it fixed. Just to let you know, there's a new version of the module 0.8.1 which shouldn't require root permission anymore.