[OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?

yes it's workable with no big problem all you need is a microcontroller with an UART , the RS232 level conveter , the compact flash , and the right firmware , la last thing is the more difficult to obtain ...

at 100 bytes for second you will have plenty of time to write to the flash, peraphs you can use a double buffer scheme ( now the micro need to have enough internal ram ! ), if the compact flash is a 3.3 V part ( ( I am not sure about supply voltage of CF ) is best to select a 3.3 V micro.

My first choiche for the micro is a pic18f part .

an interesting substitute for CF can be an MMC or SD flash memory , small footprint , simpler connector.

last thing before start : check if you are able to read from a PC a non file-system flash memory.

You certainly can under Linux. You can open a flash memory device as if it's a just a single huge file (which I believe is the usage the OP is proposing).

Under XP... good luck.

--
Grant Edwards                   grante             Yow!  Wow! Look!! A stray
                                  at               meatball!! Let's interview
                               visi.com            it!

These two paragraphs seem to contradict each other. In order for the compact flash card to be recognised by WinXP it needs a file system. If it doesn't have one your only option to access the card will be to format it. I suppose you could write a device driver (or find one) to read data off as raw data. That might be possible but I've never done it.

My gut feeling is that it would be easier to parse the FAT table from the micro than to have to futz around with WinXP internals. There are lots of code examples around and specs of the FAT file system. Its really not that tricky.

I don't know of anything that exists already but I've never looked.

Just my $0.02.

James.

Leave it to MS to make the simplest, most obvious use of a device impossible.

I suppose judging by the fiasco that was the recent US Grand Prix in Indiannapolis, one might say that MS Windows and F1 racing is a apt comparison. Both are controlled by irrational, egomaniacal dolts out to screw everybody with no regard to their customers. On purely technical gounds, I'd have to give F1 _cars_ the edge over Windows. The two organizations, OTOH, do have similarities. :)

or c) Using a decent OS like Linux that doesn't demand that there be a filesystem on a CF.

--
Grant Edwards                   grante             Yow!  ... I want FORTY-TWO
                                  at               TRYNEL FLOATATION SYSTEMS
                               visi.com            installed withinSIX AND A
                                                   HALF HOURS!!!

Can't you just buy a ready made NMEA logger? They are available.

Meindert

They will claim this is to make it user friendly (giving error messages with either just numbers or three word statements....).

Having had dealings years ago with several of the F1 teams research bods, I would agree with you about which has the technical edge!

or d) Do better search for GPS or RS232 loggers first.

--
Paul Carpenter          | paul@pcserviceselectronics.co.uk
    PC Services
              GNU H8 & mailing list info
             For those web sites you hate

I googled for "NMEA data logger" and got 11700 hits. I googled for "GPS data logger" and got 163000 hits.

Kelly

Now all you have to do is find the time to examine all

175K of them to see if one of them is optimal...

Actually I've previously posted to a GPS group Response i got was product XYZ satisfies ALL needs Actually my post had been triggered by product XYZ *not* meeting needs

But general thanks to this group. The various public responses have shown how I failed to specify my goals.

I've received private responses that open up vistas of attacking my problem that I had not considered.

I'll make a more careful repost

I believe all XP supported USB card readers expect the card to have a file system on them, because they identify themselves to XP as a mass storage device type. But there might be an alternative: you already have an RS232 interface, with data coming in at about 1kbps . Why don't you use the same interface to play it back? hook it up to a PC, at 115 kbps it will playback

100 times faster than recording. Depending on how long you plan to record, this might be acceptable. There might be serial to USB devices that can go even faster. You could even write the firmware so that during playback it (playback) can be controlled from the PC, e.g. going directly to a certain point. Some of the PIC micros have built-in UARTS and run on 3.3 V.

Mat Nieuwenhoven

Note that explicitly not requiring the device have a filesystem isn't the same as explicitly requiring the device not have a filesystem.

The device can either use or not use a filesystem and meet the stated requirement.

I don't see the reasoning behind that statement. There is no connection between a device being a mass storage device and a device requiring a filesystem. I've used dozens of various card-readers and none of them expected/required the card to have a filesystem even though they were all mass storage devices.

It's possible that XP is too stupid to deal with cards that don't have a filesystem, but that's Microsoft's damage: it has nothing to do with the USB mass storage device expecting to find a filesystem.

--
Grant Edwards                   grante             Yow!  Give them
                                  at               RADAR-GUIDED SKEE-BALL
                               visi.com            LANES and VELVEETA
                                                   BURRITOS!!

Just curious. Are the quotes include in your .sig from Zippy the Pinhead? They sound oddly familiar...

Bob

Yup. I found a big file of Zippy quotes once upon a time (as part of the Emacs "yow" command, I think). I wrote a shell script that picks one at random for each posting. It's surprising how often they seem related to the thread. Zippy's like that: you're not always sure what he's saying but it somehow seems relevent anyway.

Once upon a time, many years ago, I also had random Zippy quotes attached automatically to e-mails (even internal work-related ones). Once e-mail got to be more mainstream, I decided that wasn't a good idea. I particularly remember one recipient's reaction to a Zippy quote about the pope and a bubble-bath...

--
Grant Edwards                   grante             Yow!  I'm thinking about
                                  at               DIGITAL READ-OUT systems
                               visi.com            and computer-generated
                                                   IMAGE FORMATIONS...

Fun idea! My vote goes to Zippy for moderator;)

Bob

... snip ...

You might do well to emulate the CP/M system, as used for script (submit) files. The storage was originally based on the 128 byte sector size of an 8 inch SSSD floppy (and subsequent other formats were mapped into this). The submit file consisted of one line per sector, terminated. Although the file was a part of the file system, the only addressing necessity was sequential sectors.

--
"If you want to post a followup via groups.google.com, don't use
 the broken "Reply" link at the bottom of the article.  Click on 
 "show options" at the top of the article, then click on the 
 "Reply" at the bottom of the article headers." - Keith Thompson

My thanks to the group for providing useful input in response to a poorly defined question.

I had broken my problem statement into three parts.

1. what I wanted to accomplish
2. a view of possible solution
3. thoughts on what hardware might satisfy needs/desires/aesthetics

Unfortunately my original post pureed all into amorphous glob. My apologies.

I'll break things down in above groupings.

1. What am I looking for It might be described as "data logger" or a "very large FIFO".

The input will be an RS232 data stream terminated by of no more than 100 bytes at 4800 BAUD occurring once per second.

It shall buffer/store at least 10 mega bytes

The output shall be via USB 1. I wish to take advantage of USB speed 2. My computer has available USB port(s) 3. My computer does *not* have available serial port(s)

1. Possible solutions Flash devices are large and do not require power to maintain data. There are environments such as FORTH which can presume any mass storage device/system to be a sequence of nnn byte blocks/sectors/whatever

1. available hardware Let's just forget how badly I mangled this one ;{

Is this a better problem definition?

Actually, there's a simple solution. Format the CF card on a pc and create a single binary file which fills the entire capacity of the card. Your micro simply has to skip over the the file system information and then is free to write whatever it wants to to the bytes constituting the actual contents of the file.

You host application simply opens the file representing the whole card (less filesystem headers) and accesses it according to whatever organizational model you chose.

Not quite as simple as opening the device file representing the card itself under linux, but once you figure out how to skip past the filesystem tables not much different in actual practice.

To verify that everything is where you think it is, write a PC program that creates the filler file and fills it with incrementing numbers, then use a dump program under either linux or on your micro to examine the card and make sure the data is where you think it is (and where the filsystem tables aren't).

Does Win XP provide any way to read/write the raw sectors of the device? If not, that's the real Microsoft fsk.

As OP I say that is *KEY* !!! Actually I presumed capability of writing/reading physically sequential raw sectors.

Does any of this conflict with what I said in 'Revised draft of " [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?" ' ?

If not, that's