From: zachlac <zla...@gm...> - 2010-04-23 21:38:19
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I see 6 pwm's listed on the Gumstix sheet for the 40-pin Tobi header, but only 3 seem to be active--8, 9, and 11. 10, 0, and 1 do not seem to work. How can I debug this, and what would cause this problem? Also, using the /sys/class interface, I can only control GPIO output on 1 GPIO; the 1-wire serial, GPIO170. I can also control the PWM's this way, but none of the other GPIO's. I'm looking at pin muxing, and it seems that all you can control is IEN (input enable) and not output. Basically, any help with how to actually control GPIO, and troubleshoot these lower-level problems, is welcome. I've looked around the forum for quite a while, and I didn't find anything to specifically address these issues. -Zach -- View this message in context: http://old.nabble.com/PWMs%2C-GPIO-output%2C-muxing-tp28346507p28346507.html Sent from the Gumstix mailing list archive at Nabble.com. |
From: ekoshimo <ed....@na...> - 2010-04-27 19:24:02
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Hi Zach, I'm learning about GPIOs myself, and I haven't gotten too far with actual success yet. However, I believe I'm on my way. I've read this article at jumpnow.com titled "Overo GPIO" which gave me a good starting point. Basically I've looked in my overo's /sys/class/gpio directory to see which GPIOs are active. Then I looked at the schematic for the expansion board I'm using (SUMMIT) to see what the 40-pin header assignments are. Then I looked at the OMAP3530 Technical Reference Manual Table 7-5 to see what the GPIO definitions and possible mux values are. I see gumstix wiki articles on GPIO and GPIO event which seem like more relevant information. I'm not sure how much control there is configuring the GPIO pins at bootup; it appears there is a way with u-boot scripts and dev2mem, but I haven't uncovered any definite information as of yet. I'm also looking at what userspace functions are available - it looks like you can write a program to perform GPIO operations. I know this doesn't immediately answer your question, but I myself am trying to get results as soon as possible and this appears to be the best path for me right now. As for my goals, I'm trying to use an Overo water with the summit expansion board to basically acquire DAC signals from another board, performing calculations on those DAC signals, and then outputting the results on another serial line. Thanks, ed -- View this message in context: http://old.nabble.com/PWMs%2C-GPIO-output%2C-muxing-tp28346507p28380995.html Sent from the Gumstix mailing list archive at Nabble.com. |