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raspberrypi_usb_current [2014/08/27 21:40] (current)
admin created
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 +{{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)//
 +  * Update to latest firmware: <​code>​sudo rpi-update</​code>​
 +  * Edit **/​boot/​config.txt** <​code>​max_usb_current=1</​code>​
 +  * Reboot
 +  * 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>​
 +  * Install WiringPi: [[http://​​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
raspberrypi_usb_current.txt ยท Last modified: 2014/08/27 21:40 by admin