A request for clarification

Created Wed, 13 Jul 2011 21:58:45 +0000 by amcduino

amcduino

Wed, 13 Jul 2011 21:58:45 +0000

I understand that the various manufacturers of semiconductors want to get on the Arduino bandwagon, mainly for financial reasons. Arduino has really been dominating the market and has made a considerable dent on everyone's sales. So we have PICAXE with an Arduino Shield and no libraries; we have Basic Micro with an Arduino Shield...and no libraries. We now have Digilent yet with another Arduino clone, in fact two. This is not the complete list.

Would anyone enlighten me as to what, if anything, UNO32 offers versus the Arduino UNO or the rest of the clowns, excuse me, clones?

The Arduino UNO came along as an enhancement to the Duemilanove. The enhancements? A faster USB chip, much faster, and a different, supposedly faster, bootloader. The irony is that, although the USB chip (AT8U2) has transfer rates of 1.2mBit, the Arduino IDE will not accept anything more than 115kb!

There may be an improvement for using the UNO32 for those who like to suffer and use an external programmer to work with a PicMicro. However, not all of us, including me, care for the PicMicro line.

Last but not least, I perused the UNO32 forum, and there are truck loads of "this does not work" and "that does not work". And of course lets not forget the sparsity of documentation. Could someone direct me as to where I can find a datasheet that would explain the purpose of the six blue jumpers?

I would truly appreciate your inputs as to "why the UNO32". :roll:

Best regards Amcduino

svofski

Wed, 13 Jul 2011 23:52:52 +0000

FWIW these kits don't appear to be the best choice for those who want everything served to them on a silver plate. They have a lot of raw power but it takes some skill to handle it.

You're not required to use Arduino IDE, especially for serial communication. You can use any serial terminal emulator to talk to the board at speeds up to 1.5Mbps.

The purpose of jumpers and all other pins can be deduced by looking at the schematics, which is available in the form of PDF and Eagle CAD files.

rtestardi

Wed, 13 Jul 2011 23:56:16 +0000

No hablo business, but I can help with a technical point... :-)

Could someone direct me as to where I can find a datasheet that would explain the purpose of the six blue jumpers?

Is this what you want?

[url]http://www.digilentinc.com/Data/Products/CHIPKIT-UNO32/chipKIT-Uno32-Jumpers.pdf[/url]

There are schematics on the digilent site, too.

Basically, the jumpers allow you to bind some of the peripherals on the PIC32 to the "standard" shield pins...

A4/A5 can be used for I2C or analog input...

11-13 can be used for SPI master or slave (or of course digital I/O).

10 can be used for SPI chip select or PWM.

ron.dunn

Thu, 14 Jul 2011 00:13:19 +0000

Pins, speed and memory. And price-performance.

I've got an Arduino application which had hit the speed limits of the Mega2560. My choice was to sacrifice the accuracy of the key algorithm (heavily floating point dependant) or move to a completely different platform.

I saw the Chipkit products on Sunday morning, ordered them Sunday night, they were delivered on Tuesday, and by Wednesday night I had the whole application ported in a "start-up" mode.

That critical routine has gone from 0.38ms per iteration to 0.02ms per iteration with absolutely no changes in code.

I've yet to sort out some port/pin assignments, and I'm having trouble with the startup of the serial LCD I'm using, but I'll work on those over the next 1-2 days.

Another benefit, I've got so much more memory that I can now consider alternative algorithms for other parts of the code that will make my product even better.

I was happy with Arduino, I've got a few of them scattered around my desk, but I doubt I'll go back to slower, more constrained devices unless I find serious problems with Chipkit.

ron.dunn

Thu, 14 Jul 2011 04:34:54 +0000

The Bad (so far):

• The relationships between headers, ports and pins are all over the place like a mad woman's breakfast. If your application addresses PORTx registers you'll have to choose new pin assignments, and with the exception of REx they're scattered all over the board.

• A reset is molasses-slow - around 5 seconds compared to Ardunio < 1 second

• The LED has a mind of its own. It seems to be tied into the bootloader, it flashes right through the reset process, and for some reason I haven't figured out yet it is often lit during program execution (and I'm not using Pin13).

hairymnstr

Thu, 14 Jul 2011 12:26:30 +0000

Essentially I like the ChipKIT because it's cheaper than the Arduino, it's faster and more powerful and Microchip documentation for doing low-level stuff with the hardware peripherals is excellent these days.

At the moment the software support is good but needs improving, but there's nothing like giving a bunch of microcontoller hobbyists the hardware to get the software and documentation out quickly.

I was initially concerned that Microchip/Digilent were going to be trying to take the hobbyist market to the detriment of open hardware, but all the schematics are open, the bootloader and support software code is available. So there's no reason someone else can't start making ChipKIT clones.

Trev

Sun, 17 Jul 2011 03:19:00 +0000

So there's no reason someone else can't start making ChipKIT clones.

Indeed - http://www.dangerousprototypes.com has one almost ready to go :)