Date: Sun, 31 May 2020 16:56:58 -0300 From: "Dr. Rolf Jansen" <freebsd@cyclaero.com> To: Ian Lepore <ian@freebsd.org> Cc: freebsd-arm@freebsd.org Subject: Re: BeagleBone AI Message-ID: <3CA84BA5-FEA8-4BD8-A713-C794139170EE@cyclaero.com> In-Reply-To: <966c33ea1924c2cfab5d9e295a9239d134e03f8a.camel@freebsd.org> References: <DCF67826-C2CA-461F-9A61-F934F6FB042A@cyclaero.com> <966c33ea1924c2cfab5d9e295a9239d134e03f8a.camel@freebsd.org>
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> Am 31.05.2020 um 14:11 schrieb Ian Lepore <ian@freebsd.org>: >=20 > On Fri, 2020-05-29 at 23:21 -0300, Dr. Rolf Jansen wrote: >> ... >>=20 >> First Question: >>=20 >> What modern SBC with more than 1 I=C2=B2C bus and which can run = FreeBSD 13++ would you suggest? >>=20 >> ... >>=20 >> Two more Questions: >>=20 >> Is it reasonable to assume that FreeBSD would run on a BBAI in the = future, let=E2=80=99s say in 2 to 3 years? >>=20 >> Perhaps I could help porting FreeBSD to a BBAI. What would be the = general steps? >>=20 >>=20 >> Many thanks in advance for any suggestions, advices and = clarifications. >>=20 >> Best regards >>=20 >> Rolf >=20 > BTW, if you need drivers for any new i2c devices just let me know and > I'll see what I can do. I am pretty comfortable with register level programming, and so far I = came away with ioctl() calls for what I needed. So perhaps I won=E2=80=99t= need exactly a driver for new I=C2=B2C devices. However, I am far away = from being a perfect I=C2=B2C expert, specially when it comes to timing = and the best sequence of addressing different devices on the bus. = Perhaps, I may ask some questions when I run into problems. > Also, in my experience you can often get away with running an i2c bus > faster than 400khz if you need more bandwidth. I've never seen any > modern chip fail to work at 800khz, and most seem to work fine up to > about 1mhz; above that they become pretty unreliable. Does this =E2=80=9Eover clocking=E2=80=9C work for the ARM boards as = well? I just set the clock-frequency in the dts-overlay which activates = I2C1 of the BBB from 400000 to 800000. The bus seems to work as usual, = however, I did not yet come to check its speed. How again would I do = that? Probably there are many more questions to come :-) Best regards Rolf=
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