Hi, I am guessing here only. These GPIO are by default reserved for HDMI connection (look-up PIN assignment for beagle bone black). I think you might need to disable HDMI. See below my `/boot/uEnv.txt to disable HDMI
```sh cat /boot/uEnv.txt #Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_2.0 uname_r=3.8.13-bone68 #dtb= cmdline=quiet init=/lib/systemd/systemd ##Example #cape_disable=capemgr.disable_partno= #cape_enable=capemgr.enable_partno= ##Disable HDMI/eMMC #cape_disable=capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN,BB-BONE-EMMC-2G ##Disable HDMI cape_disable=capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN ##Disable eMMC #cape_disable=capemgr.disable_partno=BB-BONE-EMMC-2G ##Audio Cape (needs HDMI Audio disabled) #cape_disable=capemgr.disable_partno=BB-BONELT-HDMI #cape_enable=capemgr.enable_partno=BB-BONE-AUDI-02 ##enable BBB: eMMC Flasher: #cmdline=init=/opt/scripts/tools/eMMC/init-eMMC-flasher-v3.sh ``` On Wednesday, August 20, 2014 at 7:16:01 PM UTC+10, fung...@auckland.ac.nz wrote: > > > Hello! How's everything? > > I encountered strange error when running simple *.js file > setting a pin (GPIO) to output using beaglebone black Rev C, which I > received this August. > > I even reinstalled bonescript using > "npm install -g bonescript" > but still encounter the same error message. > > led = "P9_11", "9_12" worked > led = "P8_39", "P8_40", "P8_41", and many other pins > does not work with error message listed below > following "simpleDigitalOut.js": > > //==================================== > //simpleDigitalOut.js > > var b = require('/usr/local/lib/node_modules/bonescript'); > > var led = "P8_41"; > b.pinMode(led, b.OUTPUT); > > console.log("end of program"); > > //===================================== > ro...@beaglebone:/var/lib/cloud9/myProg <javascript:># node > simpleDigitalOut.js > > /usr/local/lib/node_modules/bonescript/my.js:57 > if(slot[0]) { > ^ > TypeError: Cannot read property '0' of null > at Object.exports.load_dt > (/usr/local/lib/node_modules/bonescript/my.js:57:20) > at Object.exports.create_dt > (/usr/local/lib/node_modules/bonescript/my.js:123:33) > at Object.exports.setPinMode > (/usr/local/lib/node_modules/bonescript/hw_capemgr.js:83:12) > at Object.f.pinMode > (/usr/local/lib/node_modules/bonescript/index.js:160:15) > at Object.<anonymous> (/var/lib/cloud9/myProg/simpleDigitalOut.js:4:3) > at Module._compile (module.js:456:26) > at Object.Module._extensions..js (module.js:474:10) > at Module.load (module.js:356:32) > at Function.Module._load (module.js:312:12) > at Function.Module.runMain (module.js:497:10) > ro...@beaglebone:/var/lib/cloud9/myProg <javascript:># > //===================================== > > I googled but cannot find a solution to this problem. > > It would be a great help if you can guide me through it. > your advice is very much appreciated. > > Many thanks, > Fung Yang > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
