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2446  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Arduino board & stability on: January 18, 2007, 02:20:36 pm
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The board itself is very reliable, but occasionally the serial port hangs and needs to be disconnected and then reconnected - though this might not be the Arduino's fault.  I have, however, seen this behavior when using it with both Linux and Windows boxes.  But I'm connecting through a cheap Chinese 150 foot USB cable that I know to be unreliable in electrically noisy environments.

Is this the arduino serial board?  Like many designs that try to stay simple and inexpensive, it plays the game of basically stealing voltage from one pin to get the RS232 voltage for the other.  I've had problems with other devices that do this in the past, although I haven't used the arduino serial specifically.

A true RS232 tranceiver (MAX232, MAX233, etc) may help solve these problems.

If it's really noisy you could also try to use RS422, which IIRC uses differential signalling.  Either use a serial port that's RS422 capable or convert from 422 to 232 at the computer end.

-j
2447  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: About "Nested interrupts" on: January 15, 2007, 11:39:17 am
Not sure what you mean by nested interrupts.  You generally cannot interrupt an interupt service routine (ISR).

How you handle interupts that come faster than they can be serviced is to simply let the ISR set a flag indicating that the interrupt has occured, then return control to the interrupted program.  You program's event loop (the loop() function in arduino) would then handle the interrupt.  More time sensitive interrupts would get handled first, then lower priority, then the main code of your program.

Make sense?

-j
2448  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: arduino datasheet? on: January 14, 2007, 09:09:29 am
Components have data sheets, finished products usually don't - they have manuals and schematics.  The web site is the manual for the arduino.  Check the arduino hardware page http://www.arduino.cc/en/Main/Hardware and it'll give you some useful information.  For example, the schematic will reveal that nearly all of the arduino's pins are simply wired directly to the Atmel's pins.  Check the ATmega8 data sheet for signal levels and input voltage specs.

For input voltage to the board, the 5V input expects a regulated 5VDC.  The arduino NG normally gets this from USB.  The "9V" connectors are tied to the input of the 7805 (78M05 to be precise, on my arduino NG), so you'll need to check the datasheet for a the 7805 to find that.  I think the 78xx series need 2V over the output to properly regulate, so the 7805 need a minimum of 7VDC input, and a maximum of around 35VDC input.  Almost any DC output power supply over 7V you're likely to find in your junk box should be OK.

On p245 of the ATmega8 data sheet they give electrical ratings for the inputs.  a High is a minimum of 0.7*Vcc (3.5V on a 5V arduino) and a maximum of Vcc+0.5V.  The absolute max ratings of the ATmega8 is 5.5V.

-j
2449  Forum 2005-2010 (read only) / Bar Sport / Re: First time soldering on: January 05, 2011, 03:37:13 pm
The three most dangerous things in the computing world:

1 - a hardware guy with a compiler
2 - a software guy with a soldering iron
3 - a user with an idea

smiley

-j
2450  Forum 2005-2010 (read only) / Bar Sport / Re: TI is competing with the MCP430 LaunchPad on: September 30, 2010, 01:26:23 pm
Ordered mine in June, got 'em yesterday (or was it day before yesterday?).

For $2.15 each I am certainly not complaining.

The folks at hackaday gave a short tutorial on how to use an open source toolchain under linux, which makes them more useful to me, but I suspect the most I would do with an MSP430 is make an arduino peripheral out of it.

first step, blink the LED.  Second, make it talk I2C or SPI to the arduino.  smiley

-j
2451  Forum 2005-2010 (read only) / Bar Sport / Re: TI is competing with the MCP430 LaunchPad on: July 02, 2010, 02:12:59 pm
westfw, thanks for the updates.  I ordered a couple of these in spite of the fact it "won't work" on my mac.  Looks like I was wrong, and there's a gcc for it as well.

Of course I just ordered, so there's no telling how long before I see the hardware.

-j
2452  Forum 2005-2010 (read only) / Bar Sport / Re: Didn't take 'em long..... on: November 27, 2010, 02:02:26 pm
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Excuse me, but I do beg to differ that you are the leading authority on this matter. If the official files include such text, a pure 'clone' should contain it aswell. This means that if you wan't to b*tch about this, ask the official creator of the product to use custom text on their boards. Now if those aren't released, it would simply mean that arduino has become proprietary. Choose.
Dude, you are way out of touch with reality.

The design was released as open source by the Arduino team.

The name Arduino was trademarked by the arduino team, which means they are the only ones allowed to use it.

As a third party I can say "this is an Arduino clone" because I'm not claiming the name as my own.  If I make a clone and say "this is an Arduino" I have infringed on the rights that the Arduino team has protected by means of the trademark.

The Sparkfun Arduino is the official Arduino, purchased from the Arduino team and resold.  They only thing Sparkfun did was to add retail packaging.  Its is most certainly not a fraudulent clone.


Because they have released the design as open source, anyone can release their own copy of the Arduino.  My fear is that the Arduino team may decide not to release files (e.g. PCB layout) i nthe future because cloners who are too stupid/lazy to even change the text before they send the files out for fabrication.

-j
2453  Forum 2005-2010 (read only) / Bar Sport / Re: Didn't take 'em long..... on: November 26, 2010, 08:03:56 am
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That particular seller appears to denote it as a clone..
Quite hard to miss that text, in my opinion.
I disagree. I missed it the first couple of times...

They use the ardunio name, even throwing in the trademark symbol, and use the official Arduino website name.  That makes it fraudulent, IMO.

-j
2454  Forum 2005-2010 (read only) / Bar Sport / Re: Eagle Footprint Needed on: November 24, 2010, 10:27:23 pm
Check the user contributed eagle libraries at the Eagle/Cadsoft web site here.

That crystal may be a bit fragile mounted vertically.

-j
2455  Forum 2005-2010 (read only) / Bar Sport / Re: Closed (ouch) or Open Hardware new Uno's ? on: September 27, 2010, 03:49:45 pm
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what next, processors where the VHDL/verilog is open source?

Like this?

-j
2456  Forum 2005-2010 (read only) / Bar Sport / Re: Closed (ouch) or Open Hardware new Uno's ? on: September 26, 2010, 02:56:48 pm
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The FTDI chip is just a microcontroller running a closed source firmware, this one is 1000% more open source but nobody is bitching at FTDI for not releasing their code.

Yeah, but it's sold as a USB/rs232 interface, and their drivers are cross-platform, and it work really really well.

My concerns with the 8U2 are: first and foremost, does it work as well as the FTDI?  I don't care if it's open/closed, specific/general, or anything else.  It needs to Just Work every time I plug it in.  FTDI has that nailed down.

Next, what happens if I use more than one device?  Does the 8U2 firmware/driver have provisions for identifying a particular device, so that no matter where I plug it in or when I plug it in, I know it's that particular unit?

Here's a place where the 8U2 can outshine FTDI: does it work on Solaris?  smiley

-j
2457  Forum 2005-2010 (read only) / Bar Sport / Re: Did you see this? Dinner is ready.... on: September 25, 2010, 07:39:32 am
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I have mixed feelings about the replacement of the FTDI USB controller.

Likewise.  The FTDI just works, and driver support is good.

I know there's a standard USB serial interface, but I have never seen a commercial device that actually used it.  Why?

-j
2458  Forum 2005-2010 (read only) / Bar Sport / Re: Did you see this? Dinner is ready.... on: September 25, 2010, 07:30:46 am
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I'm intrigued at what the extra 6 pin header is for.....

Probably ICSP for the USB chip.

-j
2459  Forum 2005-2010 (read only) / Bar Sport / Re: Looking for the cheapest USB-Serial (TTL) around on: August 19, 2010, 02:19:47 pm
The launchpad has a usb/rs232 chip separate from the microcontroller.  Of course, it's a TI chip, not an FTDI, but the basic architecture is the same as the arduino.

There even appears to be a dotted line, so you can hack the USB section of the PCB away from the processor section.

-j
2460  Forum 2005-2010 (read only) / Bar Sport / Re: Looking for the cheapest USB-Serial (TTL) around on: August 19, 2010, 01:45:27 pm
Hmm, you say
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What I want is the cheapest USB-TTL cable/board available
then you say
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I'll trade a new MSP430 launchpad
so, why not toss the MSP430 chip and use the USB/rs232 on the launchpad?  I mean, you've already got it, so it's cheap, right?

-j
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