00:51 < sam_moore> Hell yes
00:51 < sam_moore> PWM controlled through web browser
00:51 < sam_moore> GPIO controlled through web browser
+01:19 < sam_moore> .... And ADC read through web browser
+01:19 < sam_moore> Blergh
+01:28 < sam_moore> I think I'll take the rest of today off from MCTX3420 :S
+11:53 < sam_moore> I've analysed the crap out of sampling rates for this ADC
+11:53 < sam_moore> At least as much as I can just using the timestamps according to gettimeofday
+11:54 < sam_moore> Contrary to my first email, reading the ADC is actually really slow. And also probably the greatest source of variation in sampling rate.
+11:56 < jtanx> wow
+11:56 < jtanx> only 100Hz?
+11:56 < sam_moore> Well it looks more like 1KHz on the oscilloscope, but there's a lot of variation, it has trouble getting a trigger
+11:57 < jtanx> the cpu datasheet rates it at 200kSPS
+11:57 < sam_moore> Hmm
+11:58 < sam_moore> Well judging by the control it is something about the ADC reading that makes it really slow
+11:58 < jtanx> That's annoyng
+11:58 < sam_moore> Yeah
+11:58 < sam_moore> Also annoying is that the ADC file is generally in a different place each time they're enabled
+11:59 < sam_moore> I ended up modifying the program to take the path to the ADC file as an argument
+11:59 < sam_moore> And making run.sh do the initialisation
+11:59 < sam_moore> I figured that was better than calling system()
+11:59 < jtanx> that makes sense
+11:59 < sam_moore> Yep, we might want to set other options that run.sh can pass to it anyway
+12:00 < sam_moore> Ok, I have to stop now, I'm spending way to much time on this
+12:00 < jtanx> Haha
+12:00 < sam_moore> It's getting to the point where I'm considering writing an ADC kernel module that doesn't suck :S
+12:01 < jtanx> :S let's hope it doesn't get to that stage
+20:12 < jtanx> the pressure regulator has a 1-5vdc analogue output
+20:12 < jtanx> is this considered one of the pressure sensors?
+20:14 < jtanx> or maybe it's just not used
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+--- Day changed Mon Sep 23 2013
+08:51 -!- jtanx [
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+22:33 -!- Irssi: #mctxuwa_softdev: Total of 2 nicks [0 ops, 0 halfops, 0 voices, 2 normal]
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+14:18 < jtanx> with kernel 3.8 they decided to make life hard with device tree overlays
+14:19 < jtanx> http://e2e.ti.com/support/arm/sitara_arm/f/791/t/277811.aspx
+14:19 < jtanx> https://docs.google.com/a/beagleboard.org/document/d/17P54kZkZO_-JtTjrFuVz-Cp_RMMg7GB_8W9JK9sLKfA/pub
+14:47 < jtanx> huh
+14:47 < jtanx> http://www.youtube.com/watch?v=6gv3gWtoBWQ
+14:47 < jtanx> http://digital-drive.com/?p=146
+15:39 < sam_moore> I wonder if I can write a module that just uses /dev/adcX /dev/gpioX and /dev/pwmX
+15:40 < jtanx> that would make life simple
+15:40 < jtanx> but no
+15:42 < sam_moore> http://www.tldp.org/LDP/lkmpg/2.6/html/x569.html
+15:42 < sam_moore> Probably out of date (2.6?)
+15:45 < sam_moore> Also rt.wiki.kernel.org - realtime linux supposedly gives you better timing accuracy, although it would possibly break with our setup involving nginx
+15:46 < sam_moore> Actually it looks like there are quite a few ways for it to not work
+15:48 < jtanx> I think trying to write a kernel module would cause more grief than it's worth
+15:50 < jtanx> http://saadahmad.ca/using-pwm-on-the-beaglebone-black/
+15:51 < jtanx> I have no idea what's been updated and what hasn't
+15:51 < jtanx> as in, do we have that fix in our kernel
+15:53 < sam_moore> I don't know
+15:54 < sam_moore> We only need 1 PWM though
+16:00 < sam_moore> Or at least, last we heard there was only one. Doesn't make the system very expandable though.
+19:07 < jtanx> you know what I'll try loading an Ubuntu image from rcn to my sd card
+19:08 < jtanx> instead of from armhf
+19:08 < jtanx> armhf.com*
+19:17 < jtanx> ah screw it
+19:17 < jtanx> i'll stick with debian (but do the same thing)
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git.ucc.asn.au / matches / MCTX3420.git / blobdiff
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