Changing USB current limit in BB Black

AFAIK.

The current limit isn’t set on the source code on the uBoot per se, basically it is configured to write to TPS using i2c the current limit parameters.

There are two ways:

1.- Modifying uEnv.txt with the correct variables, i.e add “i2c mw …”
2.- Add the same on the default boot parameters.

I understand that is what Koen did on his patches against vanilla uBoot. And those parches are on BeagleBoard GitHub:

https://github.com/beagleboard/meta-beagleboard/blob/master/common-bsp/recipes-bsp/u-boot/u-boot-denx/0004-beaglebone-HACK-raise-USB-current-limit.patch

1.- Modifying uEnv.txt with the correct variables, i.e add “i2c mw …”

2.- Add the same on the default boot parameters.

I have tried both approaches, with no success. I am probably putting the “i2c mw” command in the wrong place (the value of the 0x01 register after boot is 0x3d, when I try to put 0x3e there). And I have tried to compile u-boot, but the objects I get (MLO and u-boot.img) give me an unbootable uSD card.

So I am stuck now.

(I’m building u-boot in the beaglebone itself, so I am using a native arm gcc; the examples are always based on cross-compiling environments, but I assume a native environment must also work).

Nice! I was inserting the command by itself, and I guess that is the reason why it didn’t work. Anyway, I finally succeeded rebuilding u-Boot from sources (I was missing a step, stupid me), so now the i2c mw… command is built in the code.

I’m really happy to be able to feed my bbb with a small 1A power supply instead of a bulky (and hot) 2.1A one :slight_smile: