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01:00 - 10:0010:00 - 23:00

1:17 AM
@NickHalden, I also hardly spend any time on ee hobbies. now I've just given up and stopped caring
I usually do other stuff that's design-related but not ee, like designing furniture and clothing patterns
or excercise
 
grEEts all!
 
@StaceyAnne exercise, then I would lose my wonderful figure. :)
@rawbrawb allo
 
@Kortuk allo, I see a certain some one now vandalizing posts and bad mouthing mods (principally W5V0) you guys must have broad shoulders!
 
hi @Kortuk, @rawbrawb
 
@rawbrawb have not seen him around
@StaceyAnne :)
 
1:29 AM
@StaceyAnne hello! or how ever you say it in what ever country you're in now.
 
@rawbrawb, vietnam now
but I don't know how to say hello in vietnamese yet
 
@StaceyAnne where next? - it's cool you are doing that!
 
@rawbrawb, a good couple of months in vietnam, till june-ish, then thailand
 
@StaceyAnne what determines when you move on? Visa? you doing this just as a cheap way to travel?
 
@rawbrawb, visa and if the country works for me (cost wise, internet wise, accomodation wise)
@rawbrawb, yeah, I realised that travelling in asia is cheaper than living in my home country, especially since I get a tax excemption
 
1:35 AM
@StaceyAnne and how do you find work? in country?
 
I work online as a freelance hardware designer
 
@StaceyAnne and does that work well? or is it intermittent? I guess your biggest access issue is bandwidth access. THat sounds cool, more power to you!
 
it works really well, I Had some trouble with internet in Cambodia but it's fine in Vietnam
 
@StaceyAnne so probably best if you don't have clients in country so you don't violate your visa requirements. I'm envious!
@StaceyAnne gotta run ciao
 
2:09 AM
'ello pEEplz
 
Hey guys, would dl.dropbox.com/u/18558837/motornoise.mp3 be considered a normal noise for a DC brush motor to make at lower power driven via PWM?
 
2:52 AM
@AnindoGhosh did you sleep already?
Hallo all
 
3:04 AM
ello
 
@rawbrawb, I usually end up getting a business visa in any case since they're usually for longer (>1 month) and then if i do end up picking up a client in the country, it's all cool
hi @KevinMark
 
hello
 
3:21 AM
@angelatlarge Slept 5 hours already.
@KevinMark hiya
 
@AnindoGhosh That ain't much sleep
 
@angelatlarge That's an hour more than my normal requirements.
 
I'm usually pushing 3-4 the past few weeks
Trying to get a project done
 
@KevinMark What is your PWM base frequency?
@KevinMark Sounds like PWM is at audio frequency, or a subharmonic is.
 
Using an Arduino for the microcontroller
 
3:24 AM
@KevinMark 3-4 is what I need under normal circumstances. Sometimes I end up getting less.
 
People think I'm crazy when I say I don't need a "normal" amount of sleep
 
@KevinMark Yup, that's a 490 Hz or so PWM hum. Push the PWM frequency up to 20 KHz or higher, I think.
 
That makes sense.
 
@KevinMark Nonsense. "Normal" differs between people, and depends a lot on genetics and health conditions.
 
That was my point
This is the project I've been losing sleep over. github.com/kmark/Captain Well, that's the code for it, anyway. It's fun, but deadlines suck.
 
3:28 AM
@KevinMark Use SetPWMFrequencySafe() and use only those pins which do not require Timer0
 
Cool, thanks for the library. I'll probably have to de-bloat it but it should accomplish exactly what I need.
 
@KevinMark Use pin 9 for the PWM output, it's my preferred safe pin.
 
My main concern was that I could be damaging the motor, the noise is second to having it actually work
 
@KevinMark Speaking of de-bloating, try switching to the FastWrite etc functions if you're using setPinMode or DigitalWrite etc anyplace. arduino.cc/forum/index.php/topic,46896.0.html
@KevinMark No, 490 Hz PWM won't damage the motor. Much lower and it might be problematic, much higher than 30-40 KHz would also be a problem for motors not designed for high frequency PWM.
 
I ripped it right from a 12V cordless drill
 
3:32 AM
@KevinMark 300 Hz through to 30 KHz you should be absolutely fine.
 
I need to be careful what I map ports to on the Uno so I can get the most efficient results. It's handling 2 motor drivers, a servo, a GPS, and an XBee module
 
@KevinMark Oh... hmmm then one thing to check for: The desired RPM (divided by 60) should not be a value close to the PWM frequency. i.e. for a 60,000 RPM operation, 1 KHz PWM can be disastrous - resonance, kaboom.
 
fun
So, in that instance the PWM would be too low?
 
@KevinMark I usually put together a pin map spreadsheet - scribbling down constraints etc. For instance, the Timer1 is the only one with a 16 bit timer (on the Uno), so I leave its associated PWM pins strictly for high precision timing tasks. ALso, limited pins with pin change interrupt support, so I leave those for that purpose when possible.
 
That's a good idea. Maybe a GDocs spreadsheet with each pin listed with its respective limitations and then what that pin maps to
 
3:37 AM
@KevinMark It isn't about "too low". It's just that at 60 k RPM, the natural frequency of commutation of the motor would be 1 KHz, or 2 KHz, etc, depending on design. If the PWM frequency is the same, oscillations could get out of hand.
@KevinMark Precisely.
 
oh ok
It's nice to have a project of this size come together. I haven't seen a large model boat powered by "smart" electronics.
Or at least an Arduino/ATmega
Without a doubt, a big thanks to the Stack Exchange community here. Incredibly helpful
 
3:56 AM
I need some help with fpga clocking
@StaceyAnne you there?
 
@Rick_2047 What's up?
 
@ThePhoton i do not know how to use the on board 50MHz clock and apply it to a pin in one of the modules
I wrote this line in the ucf
NET "clk_50MHz" LOC = "B8";
 
What's the name of the pin on the FPGA it's connected to?
 
@Rick_2047 yeah
 
Spartan-3E xc3s500E
@StaceyAnne do i absolutely need that ibuf stuff for my pins?
 
4:01 AM
@Rick_2047 @StaceyAnne, The one thing I noticed when you were talking before, StaceyAnne recommended using an IBUFGDS but you never said your board level clock signal was differential...Is it differential or single-ended clock between the oscillator and the FPGA?
 
@ThePhoton, he mentioned only one pin location (b8) so I assumed single ended
 
So then, isn't IBUFGDS the wrong thing to use?
Should just be IBUFG, I think
 
I used the ibufgds example because it was the quickest to find, but mentioned that
 
@StaceyAnne OK, when I was reading I didn't see that.
@Rick_2047, can you pastebin your top level module?
 
@ThePhoton yeah, wait
 
4:04 AM
The parts related to the clock signal
 
its a very simple module
 
It's the top level module for your design?
 
its just one clock divider
that is it
 
Just need to do
`wire clkb;`
`IBUFG ibufg_clk50 ( .I ( clk_50 MHz ), .O ( clkb ) );`
and then use `clkb` everywhere else in your code that you currently have `clk_50MHz`.
And clk_50MHz is the one you reference in the UCF file.
Sorry I don't know how to format code in chat.
 
do i need the '? no right?
 
4:09 AM
No that was me trying to get formatting as code
One more thing I'd look out for is that I always assume the synthesis tool is dumb as rocks.
In your loop, you do if ( ctr < 25'd25000000) ...
If the tool is dumb (and it is, but I am not promising it is really this dumb), it will try to build a 25-bit comparator to implement the < sign.
 
@ThePhoton thanks dude got it to work
where can I read up on all of this?
 
Better to do if ( ctr == 25'd25000000 ) begin /* increment slow clock */ and do the other stuff in the else clause.
@Rick_2047 You've got to spend a lot of time reading the Xilinx libraries documentation, and all the different Users Guides for the chip you're using.
 
@ThePhoton in a ucf file, if I have a array type register (count[3:0]) how do I write the net statements?
 
It's something like "count<3>", "count<2>", ... etc.
And AFAIK you have to specify each one individually
 
@ThePhoton, can i map parameters in verilog to generics in vhdl?
 
4:21 AM
@StaceyAnne If I knew any VHDL whatsoever I might be able to answer that.
 
@ThePhoton, I'm the same with verilog
 
@StaceyAnne AFAIK parameters in Verilog are compile-time constants.
You can instantiate a submodule with specified parameter values.
There is also a way to change the values of parameters in sub modules away from the module instantiation, but it's considered bad practice AFAIK
 
yeah, generics are the same
(instantiating a module with unique constants specific to that instance)
 
To be honest I'm totally self-taught in Verilog. I know coding for synthesis pretty well.
But I don't know the formal grammar,
I don't really know good practice for coding testbenches,
I don't know all the language subtleties. Just assume the synthesis tool is dumb and code to get the logic I want.
Which mostly means following the templates from the synthesis documentation.
 
I was taught vhdl by a company in the defence industry, so my code is almost completely made up of synchronus processes. with some asynchronous glue on the side. no formal HDL training in college or anything
 
4:28 AM
@StaceyAnne That explains why you know VHDL and not Verilog.
 
@ThePhoton @StaceyAnne i love both of you
2
 
ummmm
 
@ThePhoton, I've been thinking of buying myself one of these: digilentinc.com/Products/Detail.cfm?Prod=ATLYS
 
@StaceyAnne Could be fun to play with. The way you work, do you ever get to see the hardware you're coding for?
 
slightly concerned about the size though, since I'm used to working with the virtex series (so I have a better "feel" for the FPGA sizes than spartan)
@ThePhoton, nope, and it's becoming a problem. That's why I was thinking about buying a dev board to test firmware in hardware
 
4:38 AM
Do Virtex and Spartan even have the same size LUTs?
 
I think so, 6-inputs each
at least virtex 6 vs spartan 6
or are you referring to slice size? that I don't know, since xilinx changes it so often
 
It's good they're at least that similar.
But anything heavy-duty is going to depend on how many DSPs, how much BRAM, ... and Virtex is going to have vastly more resources than Spartan...
That said, just about every project I ever did for work got done in a Spartan.
If your project asignment is to design something for Virtex and you get it to fit in a Spartan, you're going to make some hardware architect look bad.
 
hey guys I removed a pin from my design and deleted the NET statement from the .ucf document, but now its giving me error for that pin " Constraint <NET "sclk" S>: NET "sclk" not found."
but i have removed sclk pin from the design
 
@ThePhoton, for now I think the spartan is going to be fine, a couple of my projects are spec'd for spartan. I might end up buying a beefy virtex board down the line if the need arises
@ThePhoton, but you're right, virtex devices are a whole other legue
 
4:58 AM
@Rick_2047 Make sure you saved both files before you compiled?
 
 
1 hour later…
6:05 AM
Have an odd issue with the Arduino where it will recieve data from the USB serial only but will gladly transmit data back to the Tx pin and USB.
In other words, the Rx pin is unresponsive on the Uno
Well the Serial object is going from USB IN -> TX PIN OUT
 
good morning @all
 
Morning
 
@KevinMark First, try a DigitalRead on that pin, and see if it works at all. Second, do you have a second Arduino?
 
morning @jippie
 
@jippie Heyaz dude!
 
6:14 AM
Yes, I tried with two arduino and the same thing happened. I'm testing to make sure that there's no issue with my other XBee since that's what's connected to those pins
 
@AnindoGhosh hey there stranger ;o)
 
Hmm. It works as-expected using a SoftwareSerial on the analog pins...
 
@KevinMark My point around two boards was, try sending data from one, receiving on the other, and see if TX/RX works both ways.
 
@StaceyAnne :)
so ... anything happened while I was asleep?
 
@AnindoGhosh yep the TX and RX pins are both functional on that board
 
6:26 AM
@KevinMark Then there's a problem outside of that tested subsystem, clearly.
 
yep, that's what I'm trying to figure out
I have a resistor in between the XBee serial and Arduino serial. Getting desperate, I'll try to replace it.
 
7:03 AM
not really sure what's up. The Arduino just must not be thinking the serial pins are connected to tsomething
 
 
1 hour later…
8:09 AM
Hello all
 
hi @GarrettFogerlie :)
 
How are you doing?
Ever get the HDMI extender project going?
 
I'm doing well. yeah I'm working on that at the moment
amongst other things
 
I haven't had the chance to work on any projects for the last week or two.
 
what have you been up to?
 
8:22 AM
I'm installing new servers in my house.
 
oh cool
 
And trying to move everything to the basement since its starting to get hot here already!
Are you still in Cambodia?
Hows everything out there?
 
I'm in Vietnam now :D
 
It's great here, I'm really enjoying it a lot.
Yep, Ho chi minh
arrived on sunday
 
8:25 AM
Wow, that's cool!
How long do you plan on staying around there?
 
till june ish
I managed to organise a 3 month visa
I try to say in one place for at least a month, moving disturbs work
so three months in the same place is great
 
Is it hard to get a visa?
Before 9/11 it used to be no problem to go from US down through central america, but now it is a bit different.
 
Most places are one month and then you have to get an extension
so 3 months off the bat was great
also I went the visa on arrival route which was a PITA and I ended up taking 1.5 hours to get through customs
 
1.5 hours isn't too bad. Thats about how long it takes to get on an airplain here :)
Have you ever heard of m0n0wall?
 
it's definitely been the longest so far on this trip. most of the time it's taken 30 min or so from landing to walking out of the airport on average (and that includes buying sim card)
 
8:33 AM
It is based on a bare-bones version of FreeBSD
 
I haven't heard of it
but that's cool
 
I'm surprised you fly, how far were you from where you are now?
 
oh, yeah, I flew. I chickened out because the bus ride is apparently quite traumatic. shortest distance I've ever flown. 200 km.
 
:) I've been on a shorter flight, but it was in a 4 seater plain.
Do you plan on staying in Ho chi minh, or seeing the rest of the country?
 
I'll see how it goes. hanoi sounds tempting, so I might end up in ho chi minh for 2 months and hanoi for one
 
8:43 AM
Is there still a lot of tensions there from the war many years ago? or is that kinda blown over?
 
I haven't really experienced much tension, I think for the locals life goes on. Everyone is very nice and helpful and have no problem with putting up with my very pathetic attempt at vietnamese
 
Is there a lot of English speakers or are you forced to pick up vietnamese?
 
The first two days I was in district one which is full of westerners. the english is very good
now I'm in an apartment in district 3, and at the local market, no one speaks english
so it's a lot of fun, hand guestures and smiles and pointing
 
I'm not familiar with districts, is that in the same city, it is just divided into districts?
 
yeah, they're just different suburbs of the city
everything is so cheap, especially food. I went to the marked and bought tons of local veggies (as much as I could carry), and it came to $15
 
8:48 AM
Wow, just looked up the temp where you are, is it ~33c?
 
yeah. humid as hell
 
airconftw
 
I hate humidity! I have to go to New York City soon, and I know it's going to be super humid.
 
so looking forward to monsoon season
 
8:49 AM
At least phoenix arizona is dry. Very hot but dry :)
 
last year I was in malaysia during monsoon season and it was so awesome
 
Is monsoon season in June?
 
may - september iirc
it's absolutely normal to walk outside after 5 min of rain and find yourself knee deep in water
 
Thats a long season. Here we have about two weeks that we call the monsoons.
Do you do any fishing?
 
not regularly, have been once or twice
my apartment is down the road from a river where tons of locals fish
 
8:56 AM
Why did you choose to travel this route, as opposed to going through Europe?
 
cheaper!
europe is next year
 
Seriously? Wow, you travel a ton!
 
I'm planning on visiting spain, greece, bulgaria, turkey
i think after europe I'll stop
i might do some of america (north and south) at some point
 
I want to go to Japan, and Australia.
 
japan is cool
 
8:58 AM
Panama and Costa Rica are some of the best places in the Americas.
Have you been to Japan?
 
no, but I studied with a couple of guys who were from there
 
When I was younger, my neighbor was from Japan, and she made it seem so cool!
 
how are you cooling your servers?
I'm having problems with my laptop in this heat, especially with how much processing i'm doing
the CPU is reaching 75+ degrees
very concerned about it
 
Thats what my system sits at.
 
is there a number where I should be concerned?
 
9:01 AM
They are just air cooled, but the room is set to 68f with AC
about 20c. But the servers keep the room hot and the AC is on 24/7
What system/cpu do you have?
 
quad i3
2.6 ghz
 
I have a quad i7, and running debian, it sits around 68-78c
 
I really need a faster pc
this thing is taking ages to synthesize and simulate code
 
For some reason, Xsensors/linux reports it being much hotter then if it was booted into windows.
 
I noticed that too
then I installed the lenovo fan control thing in linux
 
9:05 AM
That sucks. I just bought a new Macbook Pro Retina because of the 2880x1800 resolution.
What is lenova fan?
 
oh, I have a lenovo thinkpad
and there is a package that they offer that does fan control for linux
 
To answer your question, my system has been running in the 70s for the last couple years, and it still runs fine. I'd be worried if it goes above 80c, for too long.
 
I've seen mine peak at 81 a couple of times, but not for super long
 
If you can, you may want to lower the cpu frequency, so it stays a bit cooler. but this will slow it down. :(
 
I know! this is the universal problem with processing power
 
9:08 AM
Perhaps, you should take it apart, and make sure the fans and vents aren't filled with lint, etc.
 
I'm using virtualbox to run windows and work at tthe moment, and I have 3 cores and 100% execution cap on windows and 1 core for linux
and linux is still faster
 
I love virtualbox!!!
 
but if it gets too hot, I can drop the execution cap real time (!) and that helps
 
Yah, windows has way too much overhead!
What do you use windows for?
 
building FPGA firmware, work stuff
board designs
Xilinx has a linux release, and getting that working is quite high up on my to-do list
 
9:11 AM
I do most of my EE stuff in linux except board design.
 
but I have very little spare time on my hands at the moment
 
I know how that is. I have to start working on Friday, because I have a project due on Tuesday.
 
ooh, I'm thinking of buying one of these digilentinc.com/Products/Detail.cfm?Prod=ATLYS
it will make such a big difference to my work
will prob get the display add on too
:D
 
Cool!
That's far above my needs. But I have boxes of similar things, that I never end up using for more than a month :/
You really like Xilinx?
 
I've been putting off buying one for as long as possible, but at the moment it will be used for all three of the projects I'm working on
I'm most familiar with xilinx tools
so I guess I'm more comfortable with xilinx
 
9:17 AM
Can you get the Academic discount?
 
yes :D
one of my clients is a professor at RIT
I'm writing firmware for his research
 
Cool, It's actually very cheap!
 
yeah, and I'm using that same FPGA in a couple of boards I've designed
so it's perfect
I just hope the shipping isn't too much
 
That's cool. I've been trying to do some higher level programming lately. It takes too long to upgrade/port older projects.
Arm boards running linux are so cheap, its almost impossible to ignore them!
 
I got myself a rasberry pi the other day
did I tell you?
 
9:21 AM
But there is a lot of demand for good FPGA designers!
Thats cool! I did too.
What have you done with it? I used it for a media server rite now... need to figure out something cool to do with it.
 
I haven't done much with it actually, I had plans on coding an app for it but then work took off
 
I've used my rpi with the USBIP software and a WiFi card to do remote shooting / liveview with a Canon DSLR, bit sluggish but a good deal cheaper than the $1K odd for the Canon equivalent.
 
Thats cool! How does it connect to the Canon? I'm not familiar with camera stuff.
 
USB so normally you use a cable, but USBIP allows you to transport it over a network connection so it's transparent to the PC software and camera.
 
How sluggish is it?
 
9:32 AM
Probably a 500mS type delay, although even over straight USB you do get a bit of lag but probably mainly because of the WiFi. I've never used the Canon model but it might even be the same.
 
9:44 AM
@GarrettFogerlie, what's the time there? you're still noctournal?
 
2:45am. Yep
I have to drive my friend to the airport at ~4am.
We're finishing up a control system at a military base on the other side of the country.
What about you, what the time?
 
4:45pm
ha, you're -7, I'm +7
 
Does it get cold there at night, or is the temp pretty consistent?
yep
 
stays the same
I sleep with the aircon on
thankfully the power bill isn't mine to pay
 
:)
Thats cool that you can travel and still work! I have way too much electronics to be able to travel and still work.
 
9:49 AM
I'm accumulating electronics as I go along
 
Do they have daylight savings time? In arizona, we dont so it's always -7
Do you have a oscilloscope?
 
nope. no DST here. I don't have a scope, either, which might end up being a problem in the future
eventually I'll have to stop travelling and set up shop somewhere
 
lol,
someday...
 
yeh, for now I'm going to travel as much as i can
 
Is your family in SA? do you plan on going back?
 
9:55 AM
yeah, all my family is in SA. I head back once a year
 
Thats cool, is it a nice place to live?
 
SA is awesome
especially cape town
it's cheap, beautiful and nice weather
and there is tons to see
 
I wanted to go to Egypt and work my way down, when I was in school. But my family left Egypt so I never left the US.
 
what's it like where you live?
 
Desert, but the city is pretty big and spread out. So there aren't many skyscrapers, etc. But it is the hottest city in the US.
 
9:59 AM
oh wow, so you're also familiar with heat then
 
I've been in every state in the US, I love Alaska.
Yep.
 
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