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1  Using Arduino / Microcontrollers / Re: ATMega328P Bootloader Help on: Today at 03:52:03 am
I would use the Arduino IDE but when Atmel is installed you cannot open it.
That does not match my expectations, or my experience. (although, I haven't put them both on a W8.1 system.  They seem to coexist happily on XP and 7.)  Maybe you should debug this first...

2  General Category / General Discussion / Re: Disambiguation of Arduino certified, clones, derivatives, and counterfeit on: April 22, 2014, 02:49:58 am
sometimes they have problems with simple calculations
Can you point to an actual example of that?
Really bad counterfeits probably won't work at all, or have a different chip than advertised (lately there have been several instances of people ordering Atmega328-based boards, and getting a board with an ATmega8.)  And there are boards with counterfeit USB chips (prolific being widely counterfeited, in particular) that may have issues with USB drivers.  But I've never heard of a "partially functional" counterfeit giving bad results to calculations...
3  General Category / General Discussion / Re: Good practices (Arduino Programming) on: April 22, 2014, 02:28:11 am
1) Be consistent in your formatting and naming conventions.
2) Follow the local standard, if any.  (In the case of Arduino, format your code the same way that auto-format would format it.)

I think here in the arduino forums, we often fail to stress the importance of breaking up your program into appropriately sized functions, and frequently have loop() with WAY too much code in it...

Be aware of performance issues.   Things like Strings, and 64bit math, operator overloading, and calls to elegant libraries, may look simple and clean, but they can't actually magically perform better than more complicated combinations of simpler functions.  On the other hand, don't be paranoid about performance, either.  "Fast enough" is in fact fast enough, and "if it doesn't matter, it doesn't matter."
4  Using Arduino / General Electronics / Re: Where to find good single sided PCB on: April 22, 2014, 01:45:27 am
There has been a lot of progress recently in the availability and price of low-quantity, small, double-sided boards, but I haven't seen any bargains in large single-sided boards.  (Itead and Seeed do 15x20cm double-sided boards, 5 for about $80, but there's no benefit to doing single-sided.)
5  Using Arduino / Microcontrollers / Re: Atmega328 via Raspberry GPIO programming : fuses issue ? on: April 21, 2014, 09:58:06 pm
How are you doing reset when using the serial bootloader for uploading?  "-c arduino" isn't going to know about the special reset pin you've provided for SPI programming, and sharing the reset signal between a serial port and your additional reset signal could be "tricky."

Your "upload once" symptom is typical of not having an auto-reset; when there is no sketch loaded, the empty memory loops back around to the bootloader, so the bootloader essentially runs continuously.  When there's a sketch, the sketch runs instead and the upload operation  doesn't manage to reset the board to get into the bootloader.
6  Development / Suggestions for the Arduino Project / Re: Arduino Board with Parallax Multi-Processor Chip on: April 21, 2014, 03:46:50 am
I dunno.  I realized a long time ago that it is NOT useful to try to port "Arduino" to every "worthy" processor that exists.  Nor is it particularly useful to design Arduino-compatible boards with each conceivable hardware improvement.  For one things, these dilute the focus of the arduino user community.  (for instance, I sorta want a 32MHz Xmega-based arduino with a programmable FTDI VNC2 doing the USB connectivity. (USB device AND host!)  But I'm not sure how it'd be better than a Due or ChipKIT.)

I don't see how a 16-core parallel processor can be "arduino compatible" at the sw layer in any meaningful way :-(
Arduino is supposed to be SIMPLE; I regard products like Galileo to be somewhat fundamentally "misguided."  (But, what do I know!  I could have sworn that RPi would not have been as successful as it has been.)

The Prop-2 specs cannot be ignored
They can certainly be ignored until after the chip actually exists.
I'm not sure how a chip with "only" 512k memory (only 32k on each COG) is supposed to do a meaningful job of 1080p video (~2Mpixel); All sprites all the time?  (And I'm not sure how you integrate video into the arduino environment at all.)

All that said, Parallax would be foolish not to create a board with the infamous "Arduino pinout."
7  Community / Bar Sport / Re: Your latest purchase on: April 20, 2014, 05:17:19 am
I've had a lot (relatively speaking) of trouble with microUSB cables.  They seem particularly prone to having the wires break off at their connection points to the connectors :-(  If you have communications or power problems with a device that uses a microUSB connector, "suspect the cable" earlier than you might for full-sized USB.  (Also, the attachment of connectors to PCBs seems to be particularly fragile and dependent on surface mount adhesion and copper adhesion to the board.  Apply a little torque in an unexpected direction (which is easy when you have a cable hanging off the connector on a bare board), and POP - off comes the connector.)  (It's all rather annoying, since other points of microUSB are good.  It's spec'ed at more insertion/removal cycles than other usb connectors, and the "fragile" springy part is in the cheap cable instead of the more expensive (to replace) board-mount connector.  Grr.)

8  Community / Bar Sport / Re: Mouser price error of offloading old stock? on: April 19, 2014, 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.
9  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?
10  Using Arduino / General Electronics / Re: can i put leds on serial line to show activity? on: April 18, 2014, 06:38:38 pm
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.)
11  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.
12  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...
13  Using Arduino / Microcontrollers / Re: Question about Arduino Leonardo: Average Lifespan? on: April 17, 2014, 10:18:06 pm
From the atmega328 datasheet:
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.
14  Using Arduino / Microcontrollers / Re: FT232 vs 16u2 on: April 17, 2014, 07:08:20 pm
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...
15  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
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:

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)
     x = (x << 4) | c;
  } while (1);
  return x;

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