Best choice of controller + IDE (Linux) for use with MMC?

NXP has a broad range of ARM controllers. Very cost effective as well.

Codesourcery.com has GCC compilers for free for several platforms.

The NXP ARM controllers only need a serial port to program them. There is a simple tool for Linux:

I could take some work off your hands. I use NXP's ARM controllers almost exclusively.

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Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
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Richard, I cannot remember the details but I recall something about avoiding the FAT reqirements by using a single large file on the MMC cards, allowing use of low end pic's. If this is just a one off project it may be worth you having another look at it.

Do you need a file structure, or can you just dump your data sequentially or in blocks to storage? You can buy a Numonix M25P16

16Mbit/2M bytes SO8 serial flash chip for a dollar or so and interface to it through 4 port pins, SPI or just bit-bang.

John

IIRC you can find code to use SD cards in SPI mode, including a FAT file system, for the PIC24, which is pretty cheap and easy to use. The C compiler is free forever if you don't use optimization, AFAIR (but check license terms if that's important to you). The Windows-based IDE is free. I'm sure there is info out there for Linux, but I'm not familiar with it. You can also implement a USB host and use a flash drive mass memory device, with a somewhat higher end micro.

All this kind of flash memory has an upsetting tendency to just go away for substantial periods of time when you write to it (as much as hundreds of ms), even though the peak and average throughput may be quite high, so make sure you use a micro with enough RAM to buffer your data for a goodly amount of time.

...

I've thought about such a solution, but the main requirement is that the user must be able to read (and erase) stored data with as little hassle as possible, in a more or less universal way. And I find that the best way to do this is to use an MMC card.

A decade ago, I probably would have opted for a flash chip, a serial (RS-232) connection, and a handful of simple commands to retrieve the data. However, serial ports are getting increasingly rare these days, especially on laptops, so that isn't a viable solution any more.

Some sort of USB interface would in fact be favourite, but then I'd still have to store data in a file system, and/or create host drivers to read it from a flash chip -- which would mean even more overhead compared to the MMC card solution.

Richard Rasker

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http://www.linetec.nl

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This sounds really interesting, I'll think about your suggestion, and your offer for assistance -- I may not have any similar projects coming up right now, but in my experience, new applications materialize almost instantly as soon as I acquire a new skill or technological advancement. So chances are, you'll hear from me shortly.

Thanks already, best regards,

Richard Rasker

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http://www.linetec.nl

On a sunny day (Tue, 11 May 2010 15:59:44 +0200) it happened Richard Rasker wrote in :

An USB to serial adaptor is only about 10 Euro these days. For low power devices you can grab the voltage from DTR or RTS.

...

No problem there. At the most, I need to write one 512-byte block every two or three minutes or so, for a total of one hour per day max. The only time I ever had trouble in this area was with a Windows Vista machine, which would lapse into seconds or sometimes even minutes of unresponsiveness upon even the slightest attempt at data transfer. And that problem was easily fixed by installing Linux.

Richard Rasker

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http://www.linetec.nl

I have just finished an ATmega32 controller with an SD card interface.

The SD card FAT16/FAT32 code takes up less that 8K of code space.

If you going to re-design the board anyway, may as well use debugged code.

hamilton

OK, great, thanks, this looks like the easiest solution so far -- the one where someone else has done all the hard work :-)

I'll definitely look into it, and if I decide to use it and redesign the board (it'll be SMD stuff all around), the least I could do is offer you a board as well -- built according to your specifications, of course (.

Anyway, I'm very pleased with all the great responses so far. I'll take a few days to check things out, before deciding exactly what to use.

Richard Rasker

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http://www.linetec.nl

[snip]

Hello again Nico,

I'm quite interested in your offer, but perhaps my e-mail to your address hasn't reached you. Please substitute 'spamtrap' with my last name if you want to send me an a-mail message.

Thanks again, best regards,

Richard Rasker

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http://www.linetec.nl