logs archiveBotHelp.net / Freenode / #43oh / 2015 / September / 24 / 1
Amperture
Oh man, now there's a job posting I can get into, asking very specifically for MSP430 & Code Composer experience.
lastaid
hello there, currently reading through the CC3200 Timer doc, and found something weird. its says the prescaler only applies to half width timers, e.g. 16 bit. Is there any way to get a prescaler on the 80MHz clock and a 32bit counter?
i am using the timer for timestamping of data aquisition packets, but i might not have the time to properly reset the counter every 53 odd seconds
membiblio
Hello lastaid
lastaid
hello membiblio
membiblio
So lastaid what is the deal with not being able to clear a counter for 53 seconds?
lastaid - can you not either use a interrupt on timer overflow, which has no use in this circumstance or set a interrupt for a period and then reset the timer counter - the machine is sitting there running code - what is your hesitation about the every 53 seconds thing? Confusing to me. :)
lastaid
ok, i use this for timing. my employer wanted a time sync protocol, a lot of people here tried it but without any success beyond paper. i currently get good results with the cc3200 and i think if i can tweak the sync mechanism i can live with the 53seconds timer overflow.
the timer must be reset in host as well as all nodes, or else the filtering algorithm takes a s**t, i am using a kalman filter to smooth interrupt jitter
what site do you people share graphics on, i have a graph that shows this quite nice
i basically want n nodes that have the same timebase down to < 10us
Rickta59
tinypic.com
membiblio
lastaid - so you are decoding a time sync protocol from a radio receiver?
lastaid
http://de.tinypic.com/r/2s9wwo1/8
i wrote an entire time synchronization protocol for the cc3200, yes
including compensation and resync once things get meh.
as you can see on the graph, i get a few spurs at around 53
membiblio
Ok so you are reading audio from a radio and then decoding this protocol and the cc3200 is running constantly, there are no power management issues with batteries right?
lastaid
some are hidden in this ugly graph i made
noooo, no audio
i do it with wireless as in 802.11
membiblio
Where are you decoding the time sync protocol from?
lastaid
which is part of the problem
802.11, signal gets sent from a openwrt router
membiblio
ok so this is a line powered device
so what is the issue with 53 seconds - I'm not following your issue - I have no context to empathize with your issue. :)
lastaid
it will be battery powered at some point, but hefty ones, it will just be the com module of a industrial instrument
ok
wait
membiblio
ok
paused and waiting
lastaid
i am doing this for too long ^^
membiblio
btw where in the world are you? I am in Pittsburgh PA USA
Rickta59
membiblio == bender?
membiblio
Rickta59 ? I don't understand
Rickta59
heh .. nm then
membiblio
I like futurama and I know who bender is but I don't get the reference.
lastaid
i have 6 nodes, that all try to get an approximate sync that resets the timer to 0, the offset and variance of the timer i measure and compensate for on the host. problem is that i cannot "exactly" predict when i am going to overflow and for my algorithm it is better if i force a reset at a time i am not busy with the actual payload i am sending from the instrument to host
Rickta59
no it was a real person
lastaid
is this understandable?
and also i am located near cologne
greetings from cologne to pittsburg
membiblio
Yes so... why don't you reset the timer before 53 seconds and add one to another counter and thus the overflow is not a issue. But this is so straightforward you must have already thought of this. So again - your issue? :)
Greetings from Pittsburgh to Cologne!
lastaid
thanks ... i though of that, but no one has told me what data i am shuffling around, so i don't know if i have this time window of resyncing every 53 seconds (sync takes 40ms on avg)
membiblio
You have a river flowing through your city also!
lastaid
the mighty rhein
which is actually not a huge enviromental hazard anymore
membiblio
Yes we have had the same exact issue here in the past - like the 60's and 70's. People wonder why we need government... well this is one reason :)
lastaid
the rhine, at some point, was the most effective way to harvest mercury ...
sry for the language, the water was a very good source of mercury
membiblio
lastaid - are you SO close to this issue and SO woried about realtime that you have lost um... high level view and ability to compromise right at this moment? Don't let the perfect get in the way of the good. And your processor is BEEFY so why this fear?
lastaid - yes us also with the steel industry. China will be saying the same thing in 10 years and then they will go through what our cities went through to cleanup, manage and regulate.
lastaid
membiblio: yeah, aluminum purification seems to be a big issue over there
membiblio
Also the graph that you made - I'm not sure what the data points are and what I am looking at. You are dealing with inbound /digital/ data I'm assuming coming from ntp (network time protocol) servers?
lastaid
i think the processor is beefy enough but it depends on your application. you might be right though that i have lost the high level view :)
although data requirements are really broadly specified
could be up to 1MByte
membiblio
Ok I am fascinated about what you are doing and I have the 3200's here, so I know you are using Wifi right?, but I'm finding it hard to share your concern right now - with what I can gleam of your application.
lastaid
ps
membiblio
And I do want to sympathize but I think we need more to go on.
For now - just reset the timer and increment a counter and deal with it and see what that gives you. Wash, Rinse, Repeat and voila - you will be Beautiful and Lovable :)
lastaid
mh ... imagine a peak detector, that detects peaks and sorts them into 256 slots for every full wave of a 50Hz signal. it can detect up to 15 peaks per slot.
this means you have 76us to aquire, timetag and send the data away
which is quite reasonable
well until somebody else wants 200Hz Signals, and for the American Market, that will be 240Hz
and then somebody wants 500Hz, just to be on the safe side
now you are down to 7 us for everything
membiblio
So this is reading ntp data via wifi from the internet and then also doing this other acquisition thing?
lastaid
not using ntp
membiblio
Where are you getting this time data from? Radio, Satellite?
lastaid
it uses relative time, not absolute, the host then reassociates the relative time with absolute
membiblio
GPS?
Is this a direct conversion digital radio application?
lastaid
does not matter, as i am using relative time, ob the host probably some source of PTP
fortunatly not ^^ this would be insane
Rickta59
this is that power station stuff lastaid ?
membiblio
Yes but I cannot, without knowing, put myself in your shoes to imagine your issues to brainstorm assistance for/with you?
lastaid
Rickta59: yes :) right on the money
Rickta59
you are like the guy with the rock
lastaid
yes.
Rickta59
Sisyphus
lastaid
Rickta59: does partial discarge mean anything to you?
Rickta59
hmm .. images of a mad man coming at me and a gun and nothing happens ..
no
lastaid
its basically the only field where you need a quite precise rock to throw at problems
pico second discarges that degenerate and damage transformers and switchgear
Rickta59
yeah i don't know anything about high voltage stuff
lastaid
i might come on later, got to catch a bus. i will think about what you guys said and i might just realize that i am ok with the speed i got
Thanks!
Rickta59
it is great being a rubber duck
for the record he has been trying to address his issue for a long time
i think he is hoping for someone to randomly solve whatever issue he has, so he pops in from time to time
membiblio
Rickta59 what do you mean?
Rickta59
about which?
membiblio
He must work for someone like ABB.
ok back to work for me tty in a bit
Rickta59 - here is the projects that guy likes and follows - more interesting than him :) - https://hackaday.io/projects/hacker/21364/likesandfollows
Lots of cool things there - the C64 digital tape emulator - glorious idea
Rickta59 have you seen the movie Transcendence?
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