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1  Community / Bar Sport / Re: Mouser price error of offloading old stock? on: Today at 01:19:59 am
It looks like this is perhaps a "label" containing regulatory approvals and such, that you would stick on the outside of your product if it happened to contain one of their (much more expensive) modules.  Other vendors have more accurate descriptions.
2  Using Arduino / Programming Questions / C++ class data in flash on: April 18, 2014, 11:47:17 pm
Can I put all of a C++ class in flash, if none of the data elements are modified at runtime?  (It seems unlikely to be supported by the compiler, I guess: it would have to understand when to use normal memory accesses and when to use pgmspace.  Perhaps the latest version can do this?)

Can I put ANY of a class's data into flash instead of RAM?
3  Using Arduino / General Electronics / Re: can i put leds on serial line to show activity? on: April 18, 2014, 06:38:38 pm
Quote
Why would one be better than the other?
The serial data lines have +V as their idle state, so you want to wire the LEDs so that there are "off" when there is +V (active), and ON when the signal is at 0V (active.)  You can do this by connecting the plus side of the LED to the +V power supply, and the cathode to the signal, rather than the more common (in arduino-land, anyway) method of connecting the LED cathode to GND and the anode to the signal.

Note that if you have a "real rs232" signal, there is an inversion that is part of the spec, so rs232 breakouts go back to connecting between GND and signal (the signals then also go BELOW 0V, so two LEDs are good.)
https://www.flickr.com/photos/58843278@N00/13929634874/player/
4  Using Arduino / Microcontrollers / Re: Change Vendor ID and Product ID in Firmware on: April 17, 2014, 11:18:28 pm
I agree with Chagrin.  If you have a normal MEGA2560 board, it uses an Atmel 16u2 or 8u2 for the USB interface, and you'll need to reprogram that with different firmware if you want to change the VID/PID.  There should be tutorials for the reprogramming part "around"; that's also the method by which the board is reprogrammed to be something other than a serial port.
5  Using Arduino / Microcontrollers / Re: Question about Arduino Leonardo: Average Lifespan? on: April 17, 2014, 11:15:14 pm
Nah.  You correctly identify the most likely component to fail: the connectors!
Neglecting for the moment that these are often used with not-quite-matching "shield" connectors, or bare wires, which makes them relatively suspicious from the beginning, this sort of connector is usually specified for a rather small number of insert/remove cycles...
6  Using Arduino / Microcontrollers / Re: Question about Arduino Leonardo: Average Lifespan? on: April 17, 2014, 10:18:06 pm
From the atmega328 datasheet:
Quote
4. Data Retention
Reliability Qualification results show that the projected data retention failure rate is much less than 1 PPM over 20 years at 85°C or 100 years at 25°C.
Also: http://support.atmel.com/bin/customer.exe?=&action=viewKbEntry&id=266
http://www.atmel.com/about/quality/reliability.aspx
7  Using Arduino / Microcontrollers / Re: FT232 vs 16u2 on: April 17, 2014, 07:08:20 pm
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silabs cp2102 is far better behaved than legacy "ftdi" chips
How so?
I've always been impressed by FTDIs driver SW support; a bunch of other vendors took "forever" to implement anything other than windows drivers...
8  Using Arduino / Programming Questions / Re: Convert String (5-byte HEX) received via Serial to uint64 for nRF24L01+ address? on: April 17, 2014, 12:29:11 am
Quote
The RF24 library requires a uint64 value
The RF24 library is silly and inefficient, probably.  Unless it is actually doing 64bit math, something like char[5] would be a lot better on AVR-like processors (avr-gcc is known to produce particularly bad code for 64bit manipulation)

However, something like the following should work ok:

Code:
char hexCharToBin(char c) {
  if (isdigit(c)) {  // 0 - 9
    return c - '0';
  } else if (isxdigit(c)) { // A-F, a-f
    return (c & 0xF) + 9;
  }
  return -1;
}

unsigned long long hexStrToULL(char * string)
{
   unsigned long long x =0;
   char c;
   do {
     c =hexCharToBin(*string++);
     if (c < 0)
       break;
     x = (x << 4) | c;
  } while (1);
  return x;
}

9  Using Arduino / Microcontrollers / Re: FT232 vs 16u2 on: April 16, 2014, 11:55:37 pm
Well, the ft232 was certainly aimed at USB to RS232 converters, back before everyone started cheating and just doing TTL serial.
10  Using Arduino / Programming Questions / Re: Correlation matrix to calculate similarity? on: April 16, 2014, 10:05:24 pm
What is your data?
11  Using Arduino / Programming Questions / Re: Correlation matrix to calculate similarity? on: April 16, 2014, 01:00:08 am
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your teacher is telling you to do something he is unsure about? That sounds very strange
Nah.  That's a good teacher, one who doesn't limit their students' learning to what they already know.  It shouldn't happen if the class actually convers similarity, but it's easy for me to imagine a student project that could use such things, that went beyond the bounds of the class material.

I have fond memories of when I went off an did "file" stuff in my HS basic class, and my teacher essentially said "I've never done what you're doing, but don't let that stop you."
12  Using Arduino / Microcontrollers / Re: adding a new chip to uno board on: April 16, 2014, 12:31:53 am
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Doesn't the OP's comment above mean they didn't do it right ?
Irrelevant, if they're not using the bootloader.

Why do you think it's easier to distribute a boards.txt than an avrdude.conf ?
Using the 1.5 features, you should be able to set up a "board" entry that uses a different avrdude command for upload (referencing a different avrdude.conf, for example), which should then allow user to upload both to 328p and 328-based boards.   I think.
(The problem is that if you modify avrdude.conf for the 328, it no longer recognizes the 328p, right?)
13  Using Arduino / Microcontrollers / Re: adding a new chip to uno board on: April 15, 2014, 08:35:49 pm
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is there a way to edit the configuration and board files to allow the IDE to program both chips seamlessly under the uno board moniker without constantly re editing the configuration file?
In short, no.  328 isn't supported by compiler version shipped with Arduino.
Note that if you did it right, once you have bootloaders programmed, the bootloader will identify the 328 as a 328p, and you shouldn't have trouble with unmodified IDEs after that, unless you need to reprogram the bootloader.  So you can have someone with a patched avrdude config burn bootloaders for everyone (or use a tool like "optiloader" or Nick Gammon's bootloader loader),
and THEN everyone should be OK.
14  Using Arduino / Programming Questions / Re: Correlation matrix to calculate similarity? on: April 15, 2014, 08:32:06 pm
"String metric" perhaps?
http://en.wikipedia.org/wiki/String_metrics
15  Using Arduino / Programming Questions / Re: Upload bigger than 28.800bytes does't complete? on: April 15, 2014, 08:01:23 pm
There was a famous optiboot bug that hit at about that file size (long ago fixed.)
http://code.google.com/p/arduino/issues/detail?id=380&can=1&q=optiboot
I don't remember ever hearing about a similar problem in atmegaboot, and it's logic should be different enough that it doesn't have exactly the same error, but it could be related.
You could load up optiboot instead; it is known to be fixed, and is 1.5k shorter as well...
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