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31  Using Arduino / General Electronics / How do I calculate the values for an LC or PI filter? on: June 25, 2014, 11:32:40 pm
Hey guys,

So a while back I posted this thread about an issue I was having with noise from my LED drivers:
http://forum.arduino.cc/index.php?topic=150336.0

DC42 said that the noise was likely to be 1khz, and suggested some component values for an LC filter.  But he didn't explain how he arrived at those  particular values.

Since inductors are often expensive, especially ones which can handle high current, and I need one which is small as well, I want to be able to calculate the capacitors I would need for different values of inductor, so I can choose the least expensive and smallest inductor I can.

I'd also like to know how to do the same for a PI filter, as from what I've read these seem like they'd be twice as effective at the cost of one additional capacitor, which isn't too bad if I could get away with small caps.
32  Using Arduino / Audio / Re: Is it possible to interface with I2S devices? on: June 24, 2014, 03:43:33 pm
I know what the bit stream looks like.  My question was - Others have reported issues with meeting the requirements of this protocol and it sounds like it has some kind of strict timing issue.

I did some more searching and I found a bunch of discussions about it.  But I'm still not 100% clear on it.  One issue seems to be that with the standard I2S protocol you have to toggle the LR clock before you send the last bit so that causes problems if you want to use hardware SPI to do the transfer.  But there seems to be a left-justified format that might work.  But, if you were doing DMA like Paul does on his boards, then maybe again you would have a problem toggling that second clock line at the right times.  There is also the issue of timing and how tolerant the chips are of any transfer delays and whatnot.  That I'm completely uncertain about.

Anyway, it seems anything but straightforward. 
33  Using Arduino / Audio / Question about WaveHC on an 8mhz Arduino on: June 24, 2014, 03:37:09 pm
What sort of performance could I expect to see?  I don't suppose it will play 16bit 44khz mono files?  Would it play 22khz 16bit mono files?

I was thinking about using it with a 3.3V system, but I'll need a little time in between updates to update 4 RGB leds being driven by a TLC59711: 
http://www.ti.com/lit/ds/sbvs181/sbvs181.pdf

I was really hoping for 44khz audio though.
34  Using Arduino / Audio / Re: Is it possible to interface with I2S devices? on: June 23, 2014, 06:49:41 pm
Well, here's one for example:
http://www.ti.com/lit/ds/symlink/pcm1753.pdf

I2S is a standard means of talking to audio hardware.  There are variations on it, like "left justified" which are supposed to be easier to interface with.

I also found this very informative document on it:
http://www.ti.com/lit/an/slaa449a/slaa449a.pdf

That particular DAC above is 24 bit, which may be a bit much, but 16 bit per channel exists as well.
35  Using Arduino / Audio / Is it possible to interface with I2S devices? on: June 23, 2014, 11:52:04 am
I've been looking at some I2S DACs lately, but I'm concerned that I won't b able to interface with them.  I can't seem to find much about I2S here, just one bit about how the DUE has it built in, and I recall Paul Stoffregen mentioning that getting I2S to work with the Teensy 3.0 was a pain because of the clock signals or something.   

When I look at the datasheets though, the interface doesn't seem that complicated.  There appears to be three data lines, two of which are clock signals, and one clock signal is the bit clock and is 16, 32, or 64x that of the main clock.  So I guess the main clock signals the end of an integer or whatever.  Seems simple enough to bit bang if there were no other way of generating the signal.

So what's the issue?  What am I missing here?  Or am I worrying over nothing?
36  Using Arduino / Microcontrollers / Does the Micro come with the default Atmel 32U4 bootloader from the factory? on: June 22, 2014, 08:17:51 am
Does the Arduino Micro come with the default Atmel 32U4 bootloader from the factory?

I suspect not.  If not, why not?  It is incompatible with the Arduino IDE?  Or does it perhaps require the additional step of pressing a program button as with some of Atmel's other USB boards?

I ask because I was thinking about designing a 32U4 board without an ISP header on there by default, and just use the USB to program it, but that would be silly if I had to have the header there to put the bootloader on the chip in the first place.
37  Using Arduino / Microcontrollers / Re: Trying to figure out how to add A3BU XPLAINED to Xmegduino, but I'm a bit lost. on: June 17, 2014, 08:13:40 am
But where is the spec for those files so I know how to create a new entry?  Not all entries  have the same parameters.

I googled it and found several pages with specs but at least one says it's a proposed spec and I can't tell if they're official or not.
38  Using Arduino / Microcontrollers / Trying to figure out how to add A3BU XPLAINED to Xmegduino, but I'm a bit lost. on: June 16, 2014, 06:15:18 pm
Xmegaduino:
https://github.com/akafugu/Xmegaduino

I think this is the official spec for boards.txt?
https://github.com/arduino/Arduino/wiki/Arduino-IDE-1.5---3rd-party-Hardware-specification

And this tells me the processor name I need for AVRdude, and on page 2 indicates it supports DFU (FLIP v2 on the xmega):
http://nongnu.askapache.com//avrdude/avrdude-doc-6.1.pdf

But I'm pretty sure the xmega timers and stuff work differently than the mega ones, and I'm wondering if I just add a new board to boards.txt how the heck the code is going to know to use the special xmega versions of the SPI and DAC librariees for example?   Do you think their code looks for only those three variants they've defined?  Or does it go by processor?  And if so, does that mean I'm boned if my board doesn't use the same processor as one of the already defined variants?

I'm pulling my hair out here.  I gotta get this working with the Atxmega256A3BU on the explained board, and I need it to upload via USB using the DFU bootloader.  But I've got no idea what steps I need to take to get a new board profile working aside from editing that boards.txt file.
39  Using Arduino / Microcontrollers / Re: Are there any one-click tools that could be used to update firmware via usb? on: June 16, 2014, 11:33:49 am
Well, that's really rather funny, because the Mac OS is (now) a UNIX/ Linux variant where script files are how serious things have always been done!

My first computer had a tape drive.  I grew up on DOS.  I know how to write a batch file and work from a command line.  And I have no desire to return to the good old dayssmiley
40  Using Arduino / Microcontrollers / Re: Are there any one-click tools that could be used to update firmware via usb? on: June 16, 2014, 08:27:38 am
Yeah after the other fellow mentioned avrdude I thought to check for a gui for that, but the two I found have way too many options for an end user.   I don't want them to be able to change the fuse settings. 

Um... assuming the xmega even has fuses.  Which I think it doesn't.  Still... too confusing. 

Maybe something that loads an ELF file that would contain all those fuse settings?

If worst comes to worst, a batch file isn't horrible, but it does shut out all the Mac users.  I have no idea how to create something like a batch file on a Mac.

This really seems like something that should exist; I mean how many products has stuff based on the Arduino made it into, and there isn't an application you can send to an end user to load new firmware without handing them the source code and the IDE and telling them good luck?
41  Using Arduino / Microcontrollers / Re: Are there any one-click tools that could be used to update firmware via usb? on: June 16, 2014, 02:52:18 am
Yes, I mean like AVRDude, but like I said, I'd prefer not to use a batch file.  But I'd sooner use a batch file than have to write a windows application to display a file dialog and call it.  I haven't done anything like that in years and don't have the tools installed.

I'm also not sure how complicated installing AVRDude is. Unless I could just include the exe file in a zip along with the binary and batch file, it would be too complicated for my end users.

What I'd really like is to just have a single executable that pops up a file selector box and the user chooses a binary and hits upload.  I think the Teensy loader may feature something like this.  Atmel's FLIP utility is also close but I don't think it will work with the Xmegaduino bootloader I think I'm going to be stuck with if I want to just use the Arduino IDE. 
42  Using Arduino / Microcontrollers / Are there any one-click tools that could be used to update firmware via usb? on: June 15, 2014, 05:34:08 pm
Hey guys,

The Arduino micro and DUE both have a USB port for programming.  I am looking at designing a board with an Xmega using the Xmegaduino IDE which would also have USB. 

I need to be able to allow my end users to upload new firmware in a simple manner.  Right now, I've got a board with an Atmega1284 and I have them put a .bin file on an SD card and the board loads it from there.  I was thinking USB might be a better option, especially if I can make it so the board acts like a mass storage device normally so they can just drop files onto the SD card. 

So, what I was wondering is is there some utility out there which I could tell my end users to download which would allow them to simply plug the device in, select a file, and click a button to upload a binary to it?  I'd prefer not to have to do something with a batch file.
43  Community / Products and Services / Re: The Zero is upon us! on: May 21, 2014, 11:03:42 pm
Another video on the board has been posted by HackADay:
https://www.youtube.com/watch?v=SxpscquBIo4

So, what I gather from this is:

- The debugger is primarily for use with Atmel Studio.  they made no mention of debugging in the Arduino IDE.

- The SWD pins on the right side (unpopulated by default) are for using the board as a debugger when developing your own projects using the SAMD21.  I assume it plugs into the JTAG pins on the target board.

- The SPI port is not used for programming.  Presumably it is pin-compatible with the ICSP port, since it is in the same location. 
44  Community / Products and Services / Re: The Zero is upon us! on: May 20, 2014, 12:50:05 am
It seems silly to go to so much trouble.  Why would I want to use STM's debugger chip with another vendor's hardware?  I'm sure I can buy a JTAG debugger from Atmel for a reasonable price.  And I'm guessing there are open solutions out there that will work with any Arm chip.  So why be difficult about it?  You don't need to lock me in with custom chips and encryption.  Atmel has locked me in with their excellent documentation, their excellent Atmel Studio, their inexpensive ISP programmer, and all the libraries available for the Arduino.
45  Community / Products and Services / Re: The Zero is upon us! on: May 19, 2014, 01:06:41 pm
I don't like the inclusion of a second chip for debugging which won't be available for use in our own designs

What are the details on this? Are you sure the second chip won't be generally available?

I'm pretty sure.  There was a whole thread about it on AvrFreaks.  I believe one to the Atmel representatives said it was custom silicon, and that even if you reverse engineered it it would do you no good because it won't be made available for purchase.

Quote
If so, will this be the first Arduino that can't be cloned?

Yes, in the sense that you can't make an exact clone of it which features the built-in debugger. 

You should however be able to create boards which are otherwise identical, and program them. 

But you may not be able to use whatever debugging environment they add to the Arduino IDE.  Then again, it may be possible to buy a JTAG debugger from Atmel and still interface that with the IDE as you would when debugging the Due in Atmel Studio.  The debug chip on this board may in fact be the same chip in their standalone debuggers, and since it's connected via the JTAG interface, one of their standalone debuggers connected to a board with a SAMD21 processor on it may just appear to the IDE as an Arduino ZERO.  Or not.  We don't know yet.
 
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