Ben Stienstra

Linux, Unix, network, radio and more...

User Tools

Site Tools



This shows you the differences between two versions of the page.

Link to this comparison view

raspberrypi_usb_current [2014/08/27 21:40] (current)
admin created
Line 1: Line 1:
 +{{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: [[]]
 +  * 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