라즈베리 B+ USB 전류 제한해제?

wiring pi gpio 유틸 도움말을 보던 중에

어? 이런 기능이?

혹시.. 2B에도 적용되려나?

usbp   high | low

Change  the USB current limiter to high (1.2 amps) or low (the default, 600mA)

This is only applicable to the model B+

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

+ 2015.09.11

어? 2b랑 b+이랑 보드 같은거 아니었어!??!?

pi@raspberrypi ~ $ gpio usbp high USB power contol is applicable to B+ boards only. pi@raspberrypi ~ $ gpio usbp low USB power contol is applicable to B+ boards only.

차이를 모르겠다 -_-a

아무튼.. 설정은 되는데 테스트는 나중에 USB 하드라도 물려봐야지 머..

pi@raspberrypi ~ $ gpio -g write 38 0 pi@raspberrypi ~ $ gpio -g mode 38 out pi@raspberrypi ~ $ gpio -g write 38 1

I know the following:

Setting max_usb_current=1 sets the available current over USB to 1.2A (default is 600mA)

This can help if you have a decent power supply (2A, at least) and need to power something like a small external HDD or something that needs 300+ mA.

This feature is only available on the B+ and Pi model 2 (at the time of this writing)

[링크 : http://raspberrypi.stackexchange.com/.../is-setting-max-usb-current-1-to-give-more-power...]

max_usb_current

Together with the raspberry PI B+ a new config.txt setting was introduced.

  max_usb_current=1

when adding this line the USB power manager will change its output current limit (for all 4 USB ports combined) from 600mA to double that, 1200mA.

[링크 : http://elinux.org/RPiconfig#USB_Power]

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집에와서 해보니..

두개중에 하나만 해줘도 되는거 같고..

$ cat /boot/config.txt  safe_mode_gpio=4 max_usb_current=1

이렇게 38번 핀을 high 로 해도 USB 하드가 바로 전력소비가 커버되는지 삑삑삑삑

스핀들 모터가 못돌다가 조용해진다.(인식/마운트 성공)

$ gpio -g mode 38 out $ gpio -g write 38 1

결론 B+이나 2B나 같으니 2B에서도 된다!