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

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View
Caution: I explicitly stated "simplistic"  on purpose.
     I did not say simple, elegant, robust or many other adjectives.

The input sequences will be a rs232 level 4800 baud data stream of <10%0
characters terminated by a <CR><LF> pair no more frequently than once
per second.

I wish this unedited data to be stored on a 'compact flash' device which
may be read by a USB device having relatively standard interface to a
WinXP system.

I *explicitly* do not require this flash device to have a file system.
A file system might actually be an impediment.
I envision each <CR><LF> terminated "sentence" being stored in a
sequential block. [ Reading software responsible for ignoring any thing
after <CR><LF>. ]

*HOW I ENVISION DEVICE*
One RS232 input
Power switch
Record On/Off switch
RESET switch
receptacal/eject mechanism for flash device

*HOW I ENVISION USING DEVICE*
With power off insert flash device.
Attach RS232 input device.
Turn on power.
If starting new record, press RESET switch
Set RECORD to "on"
   record data
Set RECORD to "off"
EJECT flash device

What I envision:

UART receives data bytes
When byte received it is stuffed in a local RAM at address held in a
"counter"

This counter is incremented each time UART has received a character
<CR><LF> receipt triggers passing this buffer to 'compact flash' device.
Passing this data triggers another counter so next character stream
directed to another physical data block.

I have 2 questions.
1. did I make my intent clear?
2. is it workable.


BTW my intended real of application is recording data from a GPS receiver.


I any have a suitable existing device, contact me privately.
snipped-for-privacy@atlascomm.net is valid




Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
Quoted text here. Click to load it
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.

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

Quoted text here. Click to load it

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
We've slightly trimmed the long signature. Click to see the full one.
Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
Quoted text here. Click to load 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.


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

Quoted text here. Click to load it

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

Quoted text here. Click to load it

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.  :)

Quoted text here. Click to load it
   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
We've slightly trimmed the long signature. Click to see the full one.
Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?

Quoted text here. Click to load it

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

Quoted text here. Click to load it

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

Quoted text here. Click to load it

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

--
Paul Carpenter          | snipped-for-privacy@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/ PC Services
We've slightly trimmed the long signature. Click to see the full one.
Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
Quoted text here. Click to load it

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).


Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
Quoted text here. Click to load it

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

Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
Quoted text here. Click to load it

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
Quoted text here. Click to load it

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

Quoted text here. Click to load it


About half-way down the page there's a rs232 to MMC/SD card kit using a pic.
http://www.compsys1.com/workbench /



Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
Quoted text here. Click to load it

*THANK YOU* *EUREKA* *ALLELUIA*
Can you tell you have identified what I was grouping towards ;}

I was dreamin of pre-assembled and tested.
Although haven't used a soldering iron in quarter century, guess I still
remember which end burns fingers.
[ PS I'm so old that I won a Blue Ribbon in a Jr. High Science Fair with
a 6AL5 full wave rectifier ;]

I'll have to spend some serious time on that site. They have some things
there that open up a plethora of possibilities. I say plethora  to hint
at benign version of "Pandora's box".

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

Quoted text here. Click to load it

You're most welcome.


Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
Quoted text here. Click to load it

Yes, It does, I know at least a program , an hex file editor, "hex
workshop" if I remember well, that is able to open "raw" device , but I
am not totally sure about it's capabilites ( if effectively do what they
claims ), I tried with a secure digital card and an USB reader and seems
to work.

Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
Quoted text here. Click to load it

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

Meindert



Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
Quoted text here. Click to load it

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

Kelly

Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?
Quoted text here. Click to load it

Now all you have to do is find the time to examine all
175K of them to see if one of them is optimal...

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

Quoted text here. Click to load it

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




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

Quoted text here. Click to load it

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



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

Quoted text here. Click to load it

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.

Quoted text here. Click to load it

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
We've slightly trimmed the long signature. Click to see the full one.
Re: [OT?] a SIMPLISTIC RS232 data logger using some flash device --- does it exist commercially?

Quoted text here. Click to load it

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


Bob


Site Timeline