Date: Wed, 2 Oct 2013 02:14:27 +0800 From: Jia-Shiun Li <jiashiun@gmail.com> To: Paul Mather <paul@gromit.dlib.vt.edu> Cc: "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org>, ticso@cicely.de Subject: Re: BBB CPU clock (was: Re: FreeBSD on Cubieboard 2, UDOO and Galaxy Note 10.1 (Exynos). Message-ID: <CAHNYxxNxvgC7u5LhDoBwrXnEYTFkLbF1jdiPyFjxVW8_1wTk4A@mail.gmail.com> In-Reply-To: <603C57BE-8DCE-4178-B912-DBBB5CAC93B3@gromit.dlib.vt.edu> References: <CAHNYxxPtD5vgrohumwccoC_5bZv7fuV3RYK2vgLUpyEZCmOgqg@mail.gmail.com> <B8966F22-1169-4FE5-B105-4D104909723E@freebsd.org> <CAHNYxxM5Lhytd8J-A7TvaXm05sMjFM1ghROhLthyV9uCVGishQ@mail.gmail.com> <603C57BE-8DCE-4178-B912-DBBB5CAC93B3@gromit.dlib.vt.edu>
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On Tue, Oct 1, 2013 at 9:12 PM, Paul Mather <paul@gromit.dlib.vt.edu> wrote= : > What 5V adapter are you using? The one recommended by Adafruit for the B= eagleBone Black is a 5V 2A adapter. The BBB system reference manual states= , "A 5VDC supply can be used to provide power to the board. The power suppl= y current depends on how many and what type of add-on boards are connected = to the board. For typical use, a 5VDC supply rated at 1A should be sufficie= nt. If heavier use of the expansion headers or USB host port is expected, t= hen a higher current supply will be required." The BBB Wiki (http://circui= tco.com/support/index.php?title=3DBeagleBoneBlack) lists the power consumpt= ion of the BBB itself as 210--460 mA@5V depending on "activity and processo= r speed." I believe if you use capes with the BBB then you need to use the= external PSU. > > I've personally found the BBB to be a bit flaky when run via the USB OTG = connector. I prefer to run it via a 5V external PSU for stable operation. I tried several USB chargers originally for gadgets, rated 850~2000mA. I thought I overrode current limitation and voltage output of PMIC, but it did not seem to change much, almost like power output not altered at= all. Another thing strange is that the board is said to use DDR3L which requires 1.35v and TPS75217D, but the board has rev.C which defaults DCDC1 to 1.5v for DDR3. Just in case, I suppose the PMIC does not require extra steps to 'commit' changes? Basically what I did under u-boot prompt is like: U-Boot# i2c mm 24 1 00000001: 3d ? 3f 00000002: 00 ? U-Boot# i2c mm 24 0b 0000000b: 00 ? 72 0000000c: 7f ? U-Boot# i2c mm 24 0f 0000000f: 08 ? 11 00000010: 08 ? U-Boot# i2c mm 24 0b 0000000b: 00 ? 72 0000000c: 7f ? U-Boot# i2c mm 24 0f 0000000f: 08 ? 11 00000010: 08 ? U-Boot# mm 0x44e00488 44e00488: 00000007 ? 4 44e0048c: 00000007 ? U-Boot# mm 0x44e0042c 44e0042c: 00000017 ? 32017 44e00430: 00000000 ? U-Boot# mm 0x44e00488 44e00488: 00000004 ? 7 44e0048c: 00000007 ? U-Boot# boot Thanks, Jia-Shiun.
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