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From: Richard Rasker on 11 May 2010 10:08
Nico Coesel wrote:

> Richard Rasker <spamtrap(a)linetec.nl> wrote:
>
>>Hello,
>>As mentioned in a previous post, I need to store non-trivial amounts of
>>data (> 100kB) over longer periods of time, using a stand-alone
>>controller-based system.
....
>>- What controller family (brand, types) would be best suitable for the
>>job?
>
> NXP has a broad range of ARM controllers. Very cost effective as well.
>
>>- what development environments are available under Linux?
>
> Codesourcery.com has GCC compilers for free for several platforms.
>
>>- What hardware tools are available for use with Linux?
>
> The NXP ARM controllers only need a serial port to program them. There
> is a simple tool for Linux: http://www.pjrc.com/arm/lpc2k_pgm/
>
>>Since I don't expect to be working on this type of projects on a daily
>>basis, I don't want to spend many thousands of dollars on development
>>stuff -- this data acquisition project is a one-off, and I have no similar
>>future projects on the horizon.
>>
>>Thanks for any hints and suggestions,
>
> I could take some work off your hands. I use NXP's ARM controllers
> almost exclusively.

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
--
http://www.linetec.nl
From: Richard Rasker on 11 May 2010 09:59
John Larkin wrote:

> On Tue, 11 May 2010 12:40:25 +0200, Richard Rasker
> <spamtrap(a)linetec.nl> wrote:
>
>>Hello,
>>As mentioned in a previous post, I need to store non-trivial amounts of
>>data (> 100kB) over longer periods of time, using a stand-alone
>>controller-based system.
>>I got the advice here to look into MMC cards, which, contrary to SD cards,
>>don't require licensing and other strings attached.
....

> 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.

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
--
http://www.linetec.nl
From: Jan Panteltje on 11 May 2010 10:40
On a sunny day (Tue, 11 May 2010 15:59:44 +0200) it happened Richard Rasker
<spamtrap(a)linetec.nl> wrote in
<4be962d0$0$728$7ade8c0d(a)textreader.nntp.internl.net>:
>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.

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.
From: Richard Rasker on 11 May 2010 11:47
Spehro Pefhany wrote:

> On Tue, 11 May 2010 21:22:51 +0800, "Royston Vasey"
> <royston(a)vasey.com> wrote:
>
>>
>>"Richard Rasker" <spamtrap(a)linetec.nl> wrote in message
>>news:4be9341a$0$732$7ade8c0d(a)textreader.nntp.internl.net...
>>> Hello,
>>> As mentioned in a previous post, I need to store non-trivial amounts of
>>> data
>>> (> 100kB) over longer periods of time, using a stand-alone
>>> controller-based
>>> system.
>>> I got the advice here to look into MMC cards, which, contrary to SD
>>> cards, don't require licensing and other strings attached.
....
> 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.

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
--
http://www.linetec.nl
From: hamilton on 11 May 2010 12:29
On 5/11/2010 4:40 AM, Richard Rasker wrote:
> Hello,
> As mentioned in a previous post, I need to store non-trivial amounts of data
> (> 100kB) over longer periods of time, using a stand-alone controller-based
> system.
> I got the advice here to look into MMC cards, which, contrary to SD cards,
> don't require licensing and other strings attached.
>
> Now I've taken a more in-depth look at what's involved in using MMC cards,
> and I find that I the PIC controllers I'm used to (the 16F series, mostly)
> are completely unsuitable -- especially FAT support requires more far
> program and data memory than available in this series.
>
> For the same reasons, I need to migrate to a C-based development environment
> (so far, I did most things in assembly), with a possible extra complication
> that I use Linux exclusively.
>
> So I have a few more questions:
> - What controller family (brand, types) would be best suitable for the job?
> - what development environments are available under Linux?
> - What hardware tools are available for use with Linux?
>
> Since I don't expect to be working on this type of projects on a daily
> basis, I don't want to spend many thousands of dollars on development
> stuff -- this data acquisition project is a one-off, and I have no similar
> future projects on the horizon.
>
> Thanks for any hints and suggestions,
>
> Best regards,
>
> Richard Rasker

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.

http://www.roland-riegel.de/

hamilton
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