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There have been 156 items by Magpie (Search limited from 11-May 23)


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#25882 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 23 March 2012 - 02:25 AM in Project Showcase

Hi Just a word of warning. But hopefully it wont apply to you because you're using eagle. I uploaded some kicad gerbers to BatchPCB and everthing passed DRC but.... The images of the layers they sent me back were all wrong. They seemed to have mixed up my layers and I had copper traces saying R3 instead of silkscreen. I tried numerous times but could not resolve it. So hopefully you checked the images they sent back and they were good, or maybe it was just my images that were wrong. That was the reason I went with Olimex instead.


#25673 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 18 March 2012 - 07:21 AM in Project Showcase

Hi Hanzibal I used Kicad recently, I found it fairly easy to learn, compared with Eagle anyway. Also it is open source and you are not limited in anyway. Both packages have their own bizarre UI way of doing things but you get used to it. I must admit I didn't get far with Eagle, I seemed to get a mental block whenever I open it up. With KIcad I followed some video tutorials and I have managed to do just about everything. The only thing I still haven't managed is to fill an earth plane in an easy way. But I managed to import all the eagle libraries, sparkfun libraries into Kicad and make my own library. Then layout a board that passed DRC by olimex. Although I got pinged 3 Euros by then for using non standard drill holes. I would use some form of source control with your drawings, libraries as it is quite easy to do things inadvertently. So the ability to roll changes back is critical. Diptrace is also supposed to be ok but I didn't try it.


#27921 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 23 April 2012 - 05:25 AM in Project Showcase

ps. My boards arrived today, now I have to reorder my chips. Then I can see If I have a dead cat.


#25926 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 24 March 2012 - 11:43 AM in Project Showcase

Is it going to work first go? No mods. Of course it is!


#28000 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 24 April 2012 - 12:24 PM in Project Showcase

I guess one thing you can verify, is the relationship between uptime and resttime, as you said this is very odd. If you can say that "without doubt" uptime has some repeatable relation with the previous resttime then this should give us a real clue. if you can keep a full record of your projects failure times etc you might see something new. After a switch off is there some pin that holds its charge some how and you can measure it going down very slowly? The other thing I would be interested to know is do you have two of the new boards with the same symptoms?


#25488 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 14 March 2012 - 03:49 AM in Project Showcase

Just make it anyway. Olimex can spin up a couple of boards for under 40 Euros. I think it's a good project, and I would like one. I could help a fair bit as I have a bit of a background in Audio.


#27450 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 17 April 2012 - 12:20 PM in Project Showcase

After a while, the usb chip seem to get hot, no magic smoke but it smells


That's no good.
I know almost nothing about your schematic and I know you probably already know this stuff, but I will throw in my 20 cents anyway just in case there is something that could help.


It sounds like a short somewhere, hopefully not in one of the main chips.
Assuming your circuit design is good.

You can short pins with static.
Or maybe its in the pcb
or your soldering is probably crap (just kidding).

Do you have a current limited voltage supply?
If it is a short you can turn it on at a lower than normal voltage, so you get some abnormal current, say 300mA, but just enough so nothing new is cooked.
And if you have an accurate multimeter you can trace millivolts to find where the short is.

Good luck, (I'm also giving you a bit of moral support just in case the above doesn't help.)


#27875 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 22 April 2012 - 08:24 AM in Project Showcase

I hope that's it, but it's still a bit strange how it would work for an hour though.


#27629 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 19 April 2012 - 08:35 AM in Project Showcase

Oh well Look on the bright side, your still doing better than me. Olimex apparently posted me my boards a month ago, and I still haven't got them. and I've blown up all my chips in the meantime.


#27859 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 22 April 2012 - 12:25 AM in Project Showcase

Maybe just power it up when there is a lightning storm. On the good side, it sounds like you haven't damaged any hardware. It's not a software issue is it? Reboot fixes it? probably not but worth asking. Have you got an oscilloscope? With what you said about the oscillator, checking the clock would be a good place to start. You could also check all the pins to look for invalid inputs. Do you have a schematic? And a pcb file I could look at?


#27706 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 20 April 2012 - 11:42 AM in Project Showcase

At least you believe your board exists, mine must be in some sort of quantum state.


#27919 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 23 April 2012 - 03:57 AM in Project Showcase

Hi Hanzibal
There is a lot of stuff here that I am not very experienced in but ignore that and I will try to give you some extra ideas.

It seems the crystal is ok. If you cant actually get to the clock pulse because it's internal to the chip and the crystal looks good, what else can you do but assume it is good.

I am not sure your decoupling circuitry is correct, but it is hard to see from the photos.
both C5 and C7 according to the reference design should have a 1uF ceramic in parrallel to a 10uF electro. the ceramic should be as close as possible to the pins.
all other ceramics should probably be the very close to their pins as well.
Are they ceramic? some have that baby shit brown colour that they use on tantalum caps.


I guess the standard approach is to debugging digital circuits is.
  • Check all grounds. (Voltages)
  • Check all power.
  • check clock (it seems to be entirely internal, so check crystal which you have done.)
  • check all inputs for irregularity, such as indeterminate logic states, unexpected noise or waveforms, and if you can check the expected logic state is there.
after this it will be circuit specific.

Lastly what I often find is a good way to solve problems that are complicated, is to
start with something that is working and keep adding to it until you add the thing that breaks the system,
this works better than starting with something that isn't working and trying to work backwards.
In your case, did you have a breadboard that does work? does it still work? What is different?

Think to yourself this is where I earn my money. (while you look for needles in a haystack.)

The other obvious place for the problem is in software.

By the way how does it stop working, does the usb driver stop talking?<br><br>


#28002 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 24 April 2012 - 12:58 PM in Project Showcase

Hi Hanzibal

I'm hoping this is relevant, I checked the forums on your chip and people are talking about tying the output suspend pin high.

part way down page.

In the datasheet reference design it isn't tied high, and I think some people said it might be an error in the datasheet.

worth a try?


#28144 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 26 April 2012 - 02:52 PM in Project Showcase

Hi Hanzibal
I looked at the schematic and I was wondering why you're running in Bus powered mode.
Or is it bus powered mode unless the jack is plugged in?

Have you tried it in Self Powered mode?

Have you derived your circuit from fig 32?

Typical Circuit Connection 1 (Example of USB Speaker)
Figure 32 illustrates a typical circuit connection for an internal-descriptor, bus-powered, 500-mA application.



#28012 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 24 April 2012 - 01:31 PM in Project Showcase

I think were back to Shrodingers Cat, Got to go now, I think I am also at the bottom of the ideas barrel.


#28004 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 24 April 2012 - 01:05 PM in Project Showcase

Actually just hold off on the tying the pin suggestion. READ TO THE BOTTOM OF THE THREAD FIRST. like I should have.


#28010 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 24 April 2012 - 01:23 PM in Project Showcase

Did you read to the bottom of the thread? It said the datasheet was right and the tying of the output was wrong. I guess the other thing, is did you try different pcs, usb cables, usb hubs, operating systems?


#28176 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 27 April 2012 - 01:06 AM in Project Showcase

No worries, I guess one other thing you could try is contact Texas support directly. They may be able to spot the problem in 5 minutes. If you can be bothered it would be interesting to see if the chip works better in self powered mode. I was thinking that you would have a local supply anyway because of the power amp.


#28202 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 27 April 2012 - 12:59 PM in Project Showcase

Hey Hanzibal I noticed that there is an evaluation board for this chip. There is a photo and it's seems similar to yours. over at TI. But you can't download the datasheet for the eval board. Which is a problem.


#30176 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 04 June 2012 - 02:28 PM in Project Showcase

Hi Hanzibal
I saw this video about a few tips for do it yourself production. Might be useful.

I think I might get an oven like his.
Mikes Electric Stuff


#29263 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 16 May 2012 - 01:53 PM in Project Showcase

I guess I just have my head stuck in old world analogue electronics.


#28194 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 27 April 2012 - 09:11 AM in Project Showcase

Wish I had a storage cro, maybe next year. re: Changing power modes I can see your point, it would be a significant hassle and little chance of reward.


#28978 USB Audio Device - FINALLY WORKS!!

Posted by Magpie on 13 May 2012 - 11:13 PM in Project Showcase

Thanks, sorry for the delay, just got back from a week's vacation in France and Italy.

I would love to have a logo of a "Frankencat" and started thinking in line with your suggestion. I'm not much of a router but still considering to maybe integrate the amplifier on the same board, I mean it's kind of scares now plus there's two sides to play with.

Could be there's not much room for a logo then even if I go up to 100x80mm which is the limit of the free version of Eagle.

What you think?


I guess it wouldn't be good to make the board size bigger just to fit a logo, but maybe just fit whatever you can.

Also I think you should watch the separation of the power stage and the preamp stage, to make sure you don't get inadvertant feedback and hum.
It's been a while since I considered these problems, and sometimes they are not really problems at all.
I am just mentioning the following as a possibility, it is a bit of extra cost and complication.


I think what proved to be the best strategy for noise immunity was to connect the power and common as a star, back to the main power section, and pass the analogue signals around as balanced signals.
Balanced signals are balanced around the common voltage rail.

eg Unbalanced
wire 1. common 0 volts
wire 2 signal 1 sin(wt) volts.

Balanced
wire 1. common 0.5 sin(wt) volts.
wire 2 signal - 0.5 sin(wt) volts.

in either case the signal level is the same but the balanced system has more noise immunity.
I don't think you really need to go this path, but I am sure that most high end equipment uses this type of interconnection whenver possible, between boards and between devices.


#25928 [UK] Electrical Supply help

Posted by Magpie on 24 March 2012 - 12:21 PM in General Discussion

Yes I did see you said undervoltage, I just made a big presumption that only overvoltage will take out the light globes. Anyway hopefully you have found the cause of your troubles. Good Luck


#25924 [UK] Electrical Supply help

Posted by Magpie on 24 March 2012 - 11:38 AM in General Discussion

Hi Do you have smoke alarms? If you dont you should get some, even though they are annoying. Like Mario I find it difficult to see how a blowing light bulb would take out a circuit breaker. I am not saying it didn't happen but it's hard to understand. The only reasons I can think of for overvoltage on your mains are line surges or a broken neutral. Broken neutrals I would say are quite uncommon but can have serious consequences. If you ring up your supply Authority and say you suspect you have a broken neutral they might come and inspect for free. Can you get a second sparky in to verify the safety of the installation, especially the neutral and the earth connections, don't get the first one he may be dodgy, I would say it might be two hours work. Otherwise can you just turn off any dodgy circuits, at the switchboard and see if the rest of the house is ok? I wouldn't be getting the multimeter out unless you know what you are doing, and you are in a clear state of mind.



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