Date: Fri, 15 Aug 2014 17:29:34 +0200 From: Bernd Walter <ticso@cicely7.cicely.de> To: "Sulev-Madis Silber (ketas)" <madis555@hot.ee> Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: Driving WS2801 and similar LED controllers with BBB Message-ID: <20140815152933.GG60808@cicely7.cicely.de> In-Reply-To: <53EE007D.2080702@hot.ee> References: <53ECEFBE.6020500@hot.ee> <20140814183004.GP83475@funkthat.com> <53EE007D.2080702@hot.ee>
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On Fri, Aug 15, 2014 at 03:43:41PM +0300, Sulev-Madis Silber (ketas) wrote: > On 2014-08-14 21:30, John-Mark Gurney wrote: > > Sulev-Madis Silber (ketas) wrote this message on Thu, Aug 14, 2014 at 20:19 +0300: > >> Hello. > >> > >> Maybe someone else works on things like this? I basically know how those > >> are controlled, however I'm unsure what should I choose. Maybe SPI, > >> maybe I should bitbang GPIO for clock / data? Last should work with that > >> specific model (WS2801). Others use weird protocols (or "protocols"). I > >> guess I should just try something. I just let people know that I'm > >> working on that. I won't be surprised if I'm the first one to get it > >> working. > > > > I'd look at using SPI... From what I've read on the WS2801, SPI > > will do exactly what you need to do, and be the most straight forward > > solution... > > > > Only problem is, I seem to be only one who wants to use SPI from > userland... No documentation, no code. I hope that it even works in BBB. > Maybe I'll try bitbanging GPIO from Perl first. That I understand fully, > at least. And that controller seems to allow one to be sloppy or slow. Interesting - I thought there is a userland spi driver as there is for iic. But you can take a look into sys/dev/flash, which holds a few kernel drivers for different SPI flash chips. Those may help you starting with a kernel driver for your LED. -- B.Walter <bernd@bwct.de> http://www.bwct.de Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
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