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1171  Using Arduino / Microcontrollers / Re: Optiboot on AtMega328 @ 8Mhz on: October 04, 2013, 08:33:01 pm
Do the chip fuses and lock bits have to exactly match those in the boards.txt file?

After doing "Burn Bootloader" (an ICSP programmer is required) the fuses and lock bit will match, that is part of the process. But I see you want to use the internal RC oscillator, so change the fuse bytes in the boards.txt file appropriately (the boards.txt entry in the thread I linked above assumes an external crystal).

Be aware that the internal oscillator is only guaranteed by the factory to be calibrated to ±10%. Therefore async comm (and therefore the bootloader) cannot be guaranteed to work with the internal oscillator. I've actually had pretty good luck with that myself, but only at 9600 baud, and not with a bootloader, programming via ICSP and just using async comm for debugging. Given that, you might try recompiling Optiboot for 9600 baud, but there's still no guarantee.
1172  Using Arduino / Microcontrollers / Re: Optiboot on AtMega328 @ 8Mhz on: October 04, 2013, 06:22:37 pm
Do I need to run a specific version of optiboot for running at 8Mhz, or should I look into another problem?

Yes. Here is one I compiled. Note upload speed of 57600. I have not tried it using an 8U2, just bare AVRs and FTDI. So YMMV, but let us know what happens!

http://forum.arduino.cc/index.php/topic,101064.msg760450.html#msg760450
1173  Community / Website and Forum / Re: How do I find the list of all the posts I have made? on: October 04, 2013, 06:10:02 pm
Contact the NSA.  Sorry, couldn't resist smiley-wink
1174  Community / Website and Forum / Re: Arduino.cc reboot: feedback and comments on: October 04, 2013, 07:46:32 am
Did we also lose the Search link (http://forum.arduino.cc/index.php?action=search) or am I just not seeing it?
1175  Using Arduino / Project Guidance / Re: Arduino - maximum run time and fault tolerance on: October 04, 2013, 07:43:27 am
Interesting project, be sure to keep us advised if you proceed with it!

Regarding millis() rollover, it is absolutely not an issue and has been discussed ad nauseam here. Rather than trudge through all the forum threads, I'd recommend this page that Nick Gammon recently created which does a great job of explaining things.

For those unforeseen situations that require a reset, research the proper application of the watchdog timer.
1176  Using Arduino / Programming Questions / Re: Asymmetric encryption library for Arduino Uno on: October 03, 2013, 08:28:21 pm
The AVR is actually reasonably fast -- something like 2 MIPS.  The main issue is the limited RAM.

Datasheet sez...

Quote
Up to 20 MIPS Throughput at 20MHz

...that's based on "most" instructions being single-cycle. Basically 1 MIPS/MHz (I guess if a person can manage to only use  the single-cycle instructions, haha; obviously the marketing guys got into that one). So practically, an Uno for example might average somewhere between 8 and 16 MIPS.

Of course we used to say that MIPS meant "Meaningless Indication of Processor Speed"  smiley-grin
1177  Community / Bar Sport / Re: Recycling Old Circuit Boards (For Profit?) on: October 03, 2013, 06:15:44 pm
Do you think the value is based on precious metals that can be recovered from the boards? Hopefully it's not a chop shop, I was just reading this article earlier today.
1178  Using Arduino / General Electronics / Re: Ultra high reliability capacitors on: October 03, 2013, 06:11:42 pm
We probably also need to define "long lifetime" but I have a several 4000µF 50V electrolytics that have been operating (at ~40V) just fine for about 40 years now. They have an 85°C spec but are just used at room temperature, they're filters in the power supplies of audio amps. I did have a rectifier fail after a few years though. Just anecdotal evidence FWIW.
1179  Using Arduino / Microcontrollers / Re: Reprogram Arduino's own microcontroller on: October 03, 2013, 03:53:21 pm

So - does no-one believe me, or was my link wrong, or what?

Sure I believe it. Was not aware of it. Not sure if I have a parallel port around though  smiley-grin
1180  Using Arduino / General Electronics / Re: Arduino Ethernet W5100 minimal circuit on: October 03, 2013, 07:51:42 am
Can you please help me how can I connect W5100 to ATmega328 with minimal other parts? I was looking into official Arduino Ethernet Shield schematic, but it is big complicated to me: http://arduino.cc/en/uploads/Main/arduino-ethernet-shield-06-schematic.pdf

Well, that's pretty much how it's done. Compare that to what's in the W5100 datasheet. I've also used the WIZ811MJ and WIZ820io (W5200) modules. Unless we're talking considerable volume, those modules may represent a better choice. If you are really bent on rolling your own, then it sounds like you will have a learning curve.
1181  Using Arduino / Microcontrollers / Re: Reprogram Arduino's own microcontroller on: October 03, 2013, 07:40:23 am
So how exactly would I compile the bootloader source and upload it to my Uno? Avr-gcc and avrdude?

Correct, AVR-GCC, AVRDUDE, plus an ICSP programmer. But Unos come with the bootloader already programmed. Maybe I'm not sure exactly what kind of programming we're discussing.
1182  Using Arduino / Microcontrollers / Re: Reprogram Arduino's own microcontroller on: October 03, 2013, 07:30:11 am
What I mean, is can I reprogram the microcontroller without a breadboard, second microcontroller, or a dedicated programmer. Just using a computer, the Arduino, and the chip it came with.

Most Arduinos are self-contained in that respect and so only need a computer and a USB cable, so yes. Exceptions that I am aware of include the Arduino Pro and Pro Mini (these require an FTDI cable or equivalent breakout board), there may be a couple others, see http://arduino.cc/en/Main/Products for details. Apologies if I am restating the obvious.
1183  Using Arduino / Microcontrollers / Re: Reprogram Arduino's own microcontroller on: October 03, 2013, 07:05:55 am
No, that answers my question. I was hoping one could edit the source code and easily upload it to the microcontroller, but as I figured, that's not possible. Thanks anyways!

Using the bootloader or ICSP isn't easy enough?
1184  Using Arduino / Microcontrollers / Re: Reprogram Arduino's own microcontroller on: October 02, 2013, 09:08:28 pm
The direct and technical answer to your question is no, whether programmed via ICSP or async serial (bootloader) there is bound to be another "chip" somewhere to communicate with the target MCU.

Is that really your question though?  Not sure what else you might be asking so I took the words very literally  smiley-grin
1185  Community / Bar Sport / Re: Too much green! on: October 02, 2013, 09:04:23 pm
Embrace it!  MORE COWBELL!  smiley-grin   smiley-wink   smiley-confuse   smiley-cry   smiley-yell
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