{{tag>[hardware raspbian usb]}}
=====Raspberry Pi B+ USB current=====
You can change the RPI USB current limit. Keep in mind that the PSU also is able to deliver the current, e.g. 2Amp.

//All that max_usb_current=1 does is to set GPIO38 high, which in turn turns on a FET, which connects a second 39K resistor in parallel to an existing one, on pin 5 of U13, the AP2553W6 USB power manager, lifting the current limit from 0.6A to double that (1.2A)//

[[https://projects.drogon.net/testing-setting-the-usb-current-limiter-on-the-raspberry-pi-b/]]

  * Update to latest firmware: <code>sudo rpi-update</code>
  * Edit **/boot/config.txt** <code>max_usb_current=1</code>
  * Reboot

===Verify===
  * Check gpio38, value should be '1'<code>sudo bash
cd  /sys/class/gpio
echo 38 > /sys/class/gpio/export
cat /sys/class/gpio/gpio38/value</code>

**OR**

  * Install WiringPi: [[http://wiringpi.com/download-and-install/]]
  * Check: <code># gpio -v
gpio version: 2.20
Copyright (c) 2012-2014 Gordon Henderson
This is free software with ABSOLUTELY NO WARRANTY.
For details type: gpio -warranty

Raspberry Pi Details:
  Type: Model B+, Revision: 1.2, Memory: 512MB, Maker: Sony</code>
  * Check values, GPIO 38 should be '1': <code># gpio -g read 38
1</code>