Well, i have an OLS, but i've not figured out how to use it yet (how to set up the client software appropriately). Granted, that's mostly my fault since i haven't taken much initiative yet. I'm using a Rigol DS1052E oscilloscope to check the timing.
Just to note, I'm basing my timing on a baseline "clocking" with directly accessing a port for output and toggling on and off. The code i'm using for that is
So i should see three cycles, then be low for the same amount of low i got on my normal clock cycle PLUS the amount of time it takes to execute the command, then four cycles.
The PORTD commands above seem to take approx 124nS high and 124nS low (if i don't compare it to what it was it brings it down to 62nS (half the processor cycles i assume). The nS range is definitely accurate enough for what i'm using it for. I'll update with my findings when i know more. I'm also going to post the logic, procedure, and code on my website when i get it all figured out.
i'm wanting to test digital read speed of arduino in two scenarios... 1. using the built-in like x=digitalRead(pin) 2. using direct port manipulation like x=PORTC0
I can obviously test output very easily.. have it output on a pin, then put a scope on it and measure the cycle period.
[quote author="ian"]Lots and lots of flux, after that I find it way easier than through-hole.
Steady hands (using tweezers) comes with practice. I don't usually drink coffee/tea/cola, but when I do, I shake too much to do 0603 :)[/quote]
Now that i have had experience with SMD, I agree. As long as you have a 5-gallon bucket of flux on hand (maybe a slight exaggeration) and some IPA to clean up the flux mess, it's pretty easy. I'm definitely going to start using SMT for all my special projects (ones that i need to order parts for anyway, since locally i can only purchase through-hole parts and i don't have a collection of SMT parts yet).
I saw this site and it made me think about this thread... so i'm pulling it out and adding this link that may give more ideas. I'm not smart enough to judge if it's any better or worse than the suggestions already presented.
the composite signals are fairly simplistic, at least for what parts i am concerned with. You have scanlines and on the scanline it has a voltage to indicate (i believe) brightness. Then the color definition is modulated on that waveform (i'm not dealing with color). So if you had a scanline that had a black screen with white in the middle, it would look like __|----|__ (sorry for my bad artwork there) which is low then high then low (high for white). between the scanlines it goes extremely low (i don't recall if it's 0 or just really low) which is referred to as the "back porch" or clamp. then it has reference black, then the next scanline. not all scanlines are visible. for example scanline 21 can contain closed caption and tv guide type data. I think the lowest scanline for NTSC that's visible is around 23 or 30 (somewhere in that ballpark). Right now my site only has a very high level overview of my project. I'm hoping to get very detailed once the project is working well.
yeah, i'm aware of the 3dB difference (i work for the local cable company). It's actually the composite out from the set top box i'll be checking. However, thanks for the info.
I'm working on an automatic channel checking project... it scans through the channels on a set top box and monitors for audio and/or video (dependant on the parameters specified per tv channel). The work in progress is at http://www.controllerprojects.com/?p=21
What i don't know, because i have virtually no experience with, is what i need to do in order to decrease external noise from interfering with the design. Right now it's just breadboarded (which i know is bad in regards to signal ingress) and it's picking up some external influences such as the 60hz from nearby power sources. I know placing it in a metal enclosure and i assume grounding to chassis should decrease that ambient noise, but i don't know what else i can do to improve it in regards to the way i design the PCB. Any suggestions would be helpful. Also note, it is the first PCB i will have ever designed.
I couldn't find v10, but i put on v09.a and it still has the issue. I've not had a chance to take my computer in another room to make sure there's no ambient ir interference going on, but it doesn't seem to happen with the V2-PTH version.
i haven't tried the former firmwares.... for some reason i didn't think of it. When i received the IRToy i just automatically thought "i need to update to make sure i have the latest firmware". I'll try it out and reply with the status.
