I have tried to echo eqep file to slots, I have added, But in this path ' /sys/devices/ocp.3/48304000.epwmss/48304180.eqep#
when I use 'ls' command, I only get : modalias power subsystem uevent It's not display as tutorial: driver enabled modalias mode period position power subsystem uevent I hope anyone give me a recommend to complete my project,Please. Much Appreciated! On Thursday, July 25, 2013 12:19:13 AM UTC+7, tbh wrote: > > My overall goal is like the title says: I need to read a quad encoder > count, and I have a beaglebone black. Eventually, I'll be using c++. Any > help on how to proceed or links on things I should read are appreciated. > > I've seen 3 ways of reading an encoder on the beaglebone: (1)polling GPIO > pins<http://bwgz57.wordpress.com/2012/04/11/beaglebone-with-a-rotary-encoder/>, > > (2)using interrupts in a kernel driver, and (3)using the eQEP built in to > the hardware of the beaglebone SOC. I'm interested in (3) because it seems > to me that it would be the most efficient. However, it seems like most > people are using (2), and I can't find a whole lot on how to do (3). > > Here's what I have found so far in case it's useful to anyone else. > - the TRM for the bealgebone > SOC<http://www.ti.com/lit/ug/spruh73h/spruh73h.pdf>. > Section 15.4 is where the eQEP is documented. > - A thread > here<https://groups.google.com/forum/embed/?place=forum/beagleboard&showsearch=true&showpopout=true&showtabs=true&hideforumtitle=true&parenturl=http%3A%2F%2Fbeagleboard.org%2FCommunity%2FForums#!searchin/beagleboard/quadrature/beagleboard/GzRSJYjs60M/Vs67S0SRon4J>apparently > about enhancing an already working eQEP driver. > - A thread from the TI Community asking about linux drivers for > eQEP<http://e2e.ti.com/support/arm/sitara_arm/f/791/t/276433.aspx> > . > - A wiki page from a TI presentation about using eQEP with one of their > dev boards<http://processors.wiki.ti.com/index.php/Omapl137_linux_eqep_driver> > . > - Two threads with the same original post, and slightly different > responses. They are a bit over my head. > thread1<http://comments.gmane.org/gmane.linux.kernel.input/21481> > thread2 <http://en.it-usenet.org/thread/18798/20687/> > - A reference in some comments on a blog > post<http://bwgz57.wordpress.com/2012/04/11/beaglebone-with-a-rotary-encoder/>that > they got an eQEP driver working to read a quad encoder (but without > any explanation). > > I know people are working on the problem of making (3) easy to use. Is > there some other link on how to do it that is eluding me? > > If there's not, in the meantime, I'm interested in device drivers, and I > think it's practical information, so I'd like to learn as much about them > as I can. Perhaps I'll even get to the point where I can help the ongoing > eQEP effort. I'm rather inexperienced in driver writing, though. I've been > wading through the linux device drivers book <http://lwn.net/Kernel/LDD3/>, > so I guess that's a start. However, I've never recompiled my own kernel, > which it looks like I'll probably have to do, and I've never even > cross-compiled. Could somebody help me out with a place to start? > > In the meantime, I'll be looking at method (2). Thanks in advance. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
