From: Roque L. <roq...@gm...> - 2014-03-19 22:16:51
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Hi Scott, I already set the timers in capture mode from userspace with: echo 0x103 > /sys/kernel/debug/omap_mux/gpmc_ncs6 Then to check the changes I did cat /sys/kernel/debug/omap_mux/gpmc_ncs6 Which gave me the output: name: gpmc_ncs6.gpt11_pwm_evt (0x480020ba/0x08a = 0x0103), b p8, t NA mode: OMAP_PIN_INPUT | OMAP_MUX_MODE3 signals: gpmc_ncs6 | sys_ndmareq3 | mcbsp4_dx | gpt11_pwm_evt | gpio_57 | NA | NA | safe_mode Now I want to now how to access the signal GPT8_EVENT_CAPTURE so I can get the length of a pulse very accurately. Do you have any suggestion for this? P.S. Markus I got it working with GPIO events using poll() but it was not enough accurate for my application. But thank you for your help. Regards Roque 2014-03-18 15:23 GMT-06:00 Scott Ellis <sc...@ju...>: > I think you still have to write a custom kernel driver to use > the timers GPT8-GPT11 in capture mode. You can mux the > timer pads out pins 27-30 on the 40 pin expansion headers. > > I did it before for a customer a few years ago. It wasn't too > difficult. We could count pulses at 1 kHz pretty accurately > I can see from my notes. That's the highest frequency the > the customer was interested in. I don't know offhand the > upper limit. > > If you want take a look at this pwm driver to get some rough > ideas on how to get started. > > https://github.com/scottellis/omap3-pwm > > A capture driver has a different purpose, so the interface will > change. I used ioctls for everything. It's the same timers though, > just configured in PWM vs CAPTURE mode. > > The reference was the TRM section 16. > > > > -- > View this message in context: > http://gumstix.8.x6.nabble.com/Re-Help-setting-up-a-timer-in-an-overo-fire-tp4968937p4968942.html > Sent from the Gumstix mailing list archive at Nabble.com. > > > ------------------------------------------------------------------------------ > Learn Graph Databases - Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and their > applications. Written by three acclaimed leaders in the field, > this first edition is now available. Download your free book today! > http://p.sf.net/sfu/13534_NeoTech > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > -- Roque Lora Graduate Research Assistant of Electrical Engineering AggieAir Flying Circus (http://aggieair.usu.edu/) Utah State University Logan, UT, USA |