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1  Forum 2005-2010 (read only) / Troubleshooting / Re: Linux: Changing the default IDE window size on: March 07, 2007, 11:42:43 am
Thanks for the tip.

It ended up being in ~/.arduino/prefrences.txt
2  Forum 2005-2010 (read only) / Troubleshooting / Linux: Changing the default IDE window size on: March 06, 2007, 03:48:59 pm
I am running Ubuntu Linux with Beryl as the window manager.  Currently beryl has a bug that won't let java based apps resize their windows correctly.  Because of this I am trying to see if there is a way that I can send in command line arguments as to what i'd like the window size of the IDE to be. It is just a convenience for me because as of now I switch back and forth between window managers easily.  

If there is something already built into the code I'd love to take advantage of it.

Also, hats off to the cross platform-ness of your IDE.  Its a good fight to fight.
3  Forum 2005-2010 (read only) / Syntax & Programs / code execution from EEPROM or external memory? on: February 08, 2007, 03:41:51 am
Without hand coding assembly to move the hex over to somewhere execution space, is it possible to read in from the flash/eeprom and execute it?  Theoretically there is no difference between data and code in memory anyways....
4  Forum 2005-2010 (read only) / Development / Re: Arduino the RTOS? on: April 08, 2007, 12:34:09 am

So, the program that runs on the chip @ power on is different from the bootloader then?  What is the program that receives the serial upload from the computer when power on happens?
5  Forum 2005-2010 (read only) / Development / Arduino the RTOS? on: April 07, 2007, 04:32:05 pm
Is the Arduino program environment that runs the uploaded sketch (the bootloader) an RTOS?

(the reason behind the question....)

I am in college and my senior research project is Embedded Programming.  For the purposes of my research and practice, the Computer Science department bought me an arduino 0007, so I have been playing with it and developing programs and such (its been great to get my programming abilities away from that silly PC).

In my research I am learning about the RTOS (real time operating system) that is the cornerstone of larger embedded products ( cell phone, graphing calculator, etc.).
6  Forum 2005-2010 (read only) / Development / Re: If versus switch on: February 08, 2007, 03:23:37 am
I don't know too much about the Assembler code that gets uploaded to the Ard but commonly switch statements are much more efficient when compiled down to Asm code because switch statements get put together in a jump table whereas a list of if statements (or worse, if elseif .... statements) get converted into assembly if statements.  I don't remember the logistics and specifics of it all, but I do know that a jump table does a much better job at these kind of processing hurdles.  If someone was really interested I can probably find my Assembler book and put up an example.....
7  Forum 2005-2010 (read only) / Interfacing / Re: conundrum (yet another LED matrix question) on: April 09, 2007, 11:04:35 am

I am glad to hear that the code helped.  I think that the way that the datasheet specifies the timing diagram for the 7219 indicates that it should be LOW before setting the data as well, but it is obviously more tolerant.  

In any case, the code you tried is buggy.  Glad to get to the bottom of it.
8  Forum 2005-2010 (read only) / Interfacing / Re: conundrum (yet another LED matrix question) on: April 08, 2007, 12:19:39 am
I cant attest to the validity of the code posted at the link you sent me via email -- didn't see that in the playground when I was fiddling with my max chip about a month ago.  I sent (via email) you a copy of the sketch that I based my entire animation sequencer off of, but it was included with the download of the Ard IDE at the time, so you may already have it.

Now that I read about your intermittent problems with the display I would blame it on wiring of some sort.  You have two breadboards in the picture, are they sure to be good?  You said that you can manually light one LED by supplying power to a row and column pin on the display (this is good....I might continue this thought and test every single LED individually to make sure there is no short).

It could also be caused by broken wires...when you plug in the external power source it changes the angle between the Ard and the breadboard setup thus changing the way that the broken wires do or do not connect.  

I only had time to browse over the code in the playground and I personally don't like its structure but that does not say anything about how it works, which, as I said, I cannot attest to either way.  But because of the apparent disarray of the code I would think that it might be probable that it isn't guaranteed to work.  Even the original code included with the IDE (the one I sent to you in email) had some subtle bugs and useless function overhead, etc. that I removed when expanding into my own library.

Robert Carpenter
9  Forum 2005-2010 (read only) / Interfacing / Re: 8bit, 2line x 16char LCD problems on: March 10, 2007, 10:21:25 pm
I have not tried attaching the RS pin to ground but from what understand the datasheet tells me that grounding the RS pin would disable a few of the features that the read/write bus on the hitachi chip allows.  

I think that I might have gotten a bad LCD, I am going to try and get in contact with the sparkfun people and see if I can get an exchange.

10  Forum 2005-2010 (read only) / Interfacing / Re: 8bit, 2line x 16char LCD problems on: March 08, 2007, 04:04:22 pm
The library I used and the code I wrote are 8 bit.  I wrote some 4 bit code too, but converted it to 8 bit when it didn't work.

How did you find out that your vcc and gnd pins were backwards?  On my display it says those pins are for backlight.  

Oh, and where did you find a 4 bit library?
11  Forum 2005-2010 (read only) / Interfacing / 8bit, 2line x 16char LCD problems on: March 08, 2007, 03:40:34 pm
I recently bought an LCD hoping to interface it to my ARD.  It is this one:

I think it might even be the same exact lcd as the one in the tutoral ( ) but that does not matter.  The lcd driver is the same.

I downloaded the LCD library and wired up the display as indicated by the tutorial (which, based on the pinouts on my lcd, is an odd way of wiring the pins).  When I upload the basic program, all I get on the lcd is a row of squares.  The top row is solid with every character pixel lit and the bottom row is blank.  I played with the contrast pot (50k) and it works to adjust the contrast but I cannot get anything to appear on the LCD.

Looking over the datasheet linked by the vendor I wrote some of my own code and did my best to verify it but still get the same output on the display....squares.

Can anybody point me in a direction?  I can post the code I wrote if needed, but I do not think that is the problem.
12  Forum 2005-2010 (read only) / Interfacing / Re: Would this LED array work? on: March 06, 2007, 01:33:48 am
The max7219 requires three pins to operate: clock, data-in, and load.  Mine is currently pulling +5v and Gnd from the Ard power outputs on the other side too.

The basic idea with the 7219s is that you send it two bytes through data-in and then raise load.  The first of the two bytes is a memory register and the second is the value that gets stored in that memory register.  There is one register for each row of leds (rows A-G) and the byte of information stored there represents the lights that are on in that row (ie. a 01100101 would light up leds at each 1).  But the benefit is that the 7219 cycles through the led array for you at rapid pace -- you just send it a word when you want to change what it is doing.
13  Forum 2005-2010 (read only) / Interfacing / Re: Would this LED array work? on: February 27, 2007, 12:53:04 pm
Having not built one myself I cannot say.  But I can wager that it would probably work.  The hardest part for your design is that you would have to have the arduino also triggered by the clock, but that should be easily doable with interrupts.  I suppose that the only other problem you might encounter is that if the arduino does run slightly too slow you might get a large enough drift between the clock and the Ard. such that after a time your display would be completely out of sync with itself.  Though this could be easily solved by adding an extra pin to the 4022 that would trigger a second interrupt to reset the internal count of the ard.

Some good switching transistors and you could probably get something to work.  

Though I will speak for the benefit of the Max chip: (this time from experience) the ability to update one row of the leds at a time lends itself very nicely to a complex animation routine running on the Ard while the Max takes care of all the blinking.  Yes you are limited to 63 leds / max7219 chip.  I am not sure what the program you are seeking to display will do, but when you add on programming code to cycle through the display and blink each led on top of it you will start to see some lag.

The ard might not be for you, but think through what you are trying to do and try not to reinvent the wheel in the process ;-).
14  Forum 2005-2010 (read only) / Interfacing / Re: external RAM for arduino? on: February 08, 2007, 03:11:04 am
Not that I could give any advice on how to make it work, but in browsing Jameco's catalog I see EEPROM and FLASH memory in serial versions.  For example, the ST Serial flash memory I am looking @ is 20MHz, 3V, SPI bus for <$2.00 (#659913).

I would like very much to be able to hook up extra memory to the serial pins too.
15  Forum 2005-2010 (read only) / Exhibition / Re: Office Door Sign on: September 17, 2007, 02:07:42 pm
:-)....that would kind of be a rube golberg type knocker, would it not?
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