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601  Forum 2005-2010 (read only) / Frequently-Asked Questions / Midi-Sequencer - how to? on: October 16, 2010, 07:38:37 pm
Ok, I'm starting to think how my Midi-Sequencer project could work. Since the memory size of the Arduino-Mega is small (8Kb) I can't have the sequence on memory, so I will have to use a SD-Card for that.

The idea is to have Patterns, Song and Events, 3 structures. But I don't know how I will manage that on the SD card and still have things working.

Keep in mind that this is a RECORDER too, so its not just playing back a .midi file, not that simple. ;-)

Anyway, next week I will start brainstorming about this, and see what happens. :cool:

I'm still considering using another chip, like the Netduino or FEZ Panda. But .NET C# seems a bit weird to use, first since its MS, and second its interpreted, so I may not get the 72Mhz of the chip anyway... but heck, depending how the Arduino code turns to be, I may take a look at the .NET alternative.  :-[

602  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Is Arduino code interpreted? Fez Panda .NET x ? on: October 16, 2010, 01:01:43 pm
Humm, but lets be fair, it does have native calls too, I just couldn't find a list yet...  :smiley

Here's some extra info:

How does .NET Micro Framework work? Is it fast?
.NET Micro Framework is a very large set of libraries and a core CLR (interpreter).When you write an application in Visual Studio and run it, Visual Studio will transfer your code to the device and store it in a reserved region. This region of the chip is reserved for your managed application. Note that your application is only what you write, it doesn't include the NETMF libraries since they are already stored on the device via the firmware.

Lets say you write a program to read XML files. Your program will be simple. The complex work is done in FAT file system and XML libraries. Those libraries are already included in the framework (in the firmware).

Now, is it fast? Yes, it is fast depending on if you write your code right. It is a fact that managed code runs much slower than native code. Managed code runs checks at runtime, so for example when you access an array in C/C++, you can easily go over the array boundary undetected and overwrite some random memory. This is an extremely difficult bug to catch. Modern managed languages like C# check every time you access an array to see if you are within the boundaries or not. Such checks are great but they have their performance penalties. The managed application is also interpreted, which also runs slower than native code. So if you're making a function that encrypts data, it will run too slow. Why? Because all the encryption code is interpreted. This is why NETMF includes a large set of libraries to accomplish many things including cryptography, for our example. When you try to encrypt the data, you will simply be passing your data onto the internal code which is not interpreted and it runs very fast.

Someone can comment and say, I can toggle a pin faster on an 8bit micro than I can on NETMF devices! This is correct, but what kind of project only toggles a pin? Make a decently sized project and then compare speed. Try our example from earlier, read an XML file from a USB thumb drive and parse it. 8bit devices will probably not be capable of doing so and if they did it will be slower than NETMF. In short, use the built-in functions as much as you can and your project will run fast.

So, where can I get a list of those functions that runs faster?  smiley-sad

603  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Is Arduino code interpreted? Fez Panda .NET x ? on: October 16, 2010, 12:57:00 pm
That's what I was thinking. ;-) And it has more RAM, BUT, with .NET on the thing been interpreted, its like 1 byte...  ;D Sorry, couldn't resist.

I was just wondering about it. I don't like MS anyway. What I like about the Arduino is that its REALLY open-source, no MS BS involved...

Thanks, that's exactly what I needed to know. :cool:

604  Forum 2005-2010 (read only) / Frequently-Asked Questions / Is Arduino code interpreted? Fez Panda .NET x ? on: October 16, 2010, 12:20:39 pm
Guys, just trying to understand one thing. Is the Arduino code interpreted?

I wonder about this, as the Arduino board I'm looking at is 16Mhz 8 bits, while Fez Panda is 72Mhz 32 bits.

BUT, Fez Panda runs .NET interpreted code, so you don't actually get 72Mhz from what I could tell, right?

I will check the list of .NET C# functions Fez Panda supports without interpretation, so I know how it will run against an Arduino Mega, for instance.

Thanks, Wk
605  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: PCB Creating - What Software and Online Company? on: October 14, 2010, 01:30:07 pm
Thanks. That's good to know.  8-)

Still, I'm far from doing my PCBs anyway, but I wanted to start playing around with the software just to organize things up.

606  Forum 2005-2010 (read only) / Frequently-Asked Questions / PCB Creating - What Software and Online Company? on: October 14, 2010, 01:04:32 pm
Guys, around 4 years ago, I was using an online company that had a free PCB software that was integrated with the company system. So it would actually tell me how much the design would cost to run and let me order directly from the software. But I don't remember the name of the company, as I wasn't planning on doing any PCB designs...

Anyone knows something like this?


Best Regards, WilliamK
607  Forum 2005-2010 (read only) / Frequently-Asked Questions / Flash update from SD Card - possible? on: October 15, 2010, 05:12:22 am
Is it possible to update the flash of an Arduino via SD Card? Just wondering about this.

608  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: MCP4725 DAC for Sounds? on: October 14, 2010, 10:00:16 am
Ah, good to know, thanks bud.  8-)

In any event, I'm FAR from doing any sound-based stuff anyway. I was just wondering about this, as its very cheap...

609  Forum 2005-2010 (read only) / Frequently-Asked Questions / MCP4725 DAC for Sounds? on: October 14, 2010, 09:48:01 am
Just wondering if I could use SparkFun breakboard for the MCP4725 DAC 12 bits to play audio sounds?

610  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Digital MIDI sequencer - will this work? on: October 14, 2010, 08:45:30 am
Thanks bud. I'm not actually looking into a .mid format, but rather my own format, as this will be a multi-track sequencer, and not a midi-player. Of course, with time I could make it export .mid files.

I'm getting the Arduino MEGA, so I have more memory and more I/Os for other things, that I plan on using on another project. ;-)

And yes, SD looks the way to go, I'm already aware of the memory limitations of the Arduino.

Thanks again. Best Regards, WilliamK
611  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Digital MIDI sequencer - will this work? on: October 13, 2010, 02:40:57 pm
No one?  :'(
612  Forum 2005-2010 (read only) / Frequently-Asked Questions / Digital MIDI sequencer - will this work? on: September 30, 2010, 02:08:02 pm
Guys, I used to own a Roland MC-50 MKii and now I have a Roland PMA-5. But they are both too old and hard to use. So I was thinking on doing my own MIDI Sequencer with the Arduino. But the thing is, I can't figure out if the Arduino speed and memory will be enough for a project like this. I was hoping to have multiple-midi-tracks, Midi In and Out.

I'm used to C++, so that's not a problem. ;-) I just worry the memory usage. Maybe I could keep all the buffers in code and just use an external SD card for storage. (Save/Load) Or something like that.

I saw the EEprom modules, but they are expensive, and I think a SD card would be better, as I could backup files to my computer if I wanted to.

Anyway, any ideas on this subject?

Thanks, WilliamK
613  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Keypad shield - how many pins left? on: October 13, 2010, 03:37:27 pm
Ah, I also need to connect a MIDI IN and MIDI OUT, so that's some extra pins too.  8-)

614  Forum 2005-2010 (read only) / Frequently-Asked Questions / Keypad shield - how many pins left? on: October 13, 2010, 03:25:55 pm
Guys, if I use the following shield:

How many pins can I still use? I want to hock up an extra EEPROM set from this:

Also, do I need the sensor shield or can I just connect directly to the pins?


615  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: What's faster to read/write: SD card, USB Pen, ... on: October 13, 2010, 08:31:17 pm
Thanks guys. So SD card it is, as its easy to backup to a computer, compared to an extra EEPROM. ;-)

And yes, been a midi sequencer the SD card read/write speed should be enough.

I'm also taking a look at the XMOS kit, which is also great, but too expensive for me right now... :-(

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