27937 Parallax Inc, 27937 Datasheet - Page 2

• Manufacturer Part Number: 27937
• Description: MEMORY STICK DATALOGGER
• Manufacturer: Parallax Inc

Specifications of 27937

• Main Purpose: Memory, Data Logger
• Embedded: Yes, Other
• Utilized Ic / Part: VNC1L-1A
• Primary Attributes: Saves Data to a USB Flash Drive, Headers for Easy Connections
• Product: Microcontroller Accessories
• Interface Type: USB
• Operating Supply Voltage: 5 V
• Board Size: 50 mm x 22 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Resources and Downloads
Check out the Memory Stick Datalogger product page for example programs, AppNotes, datasheet and
more:
http://www.parallax.com/detail.asp?product_id=27937
Theory of Operation
The heart of the Memory Stick Datalogger is the Vinculum Embedded USB Host Controller IC by FTDI
(available through Parallax Inc.). This integrated circuit allows the implementation of USB Host Controller
functionality within products without having to deal with the low-level USB protocol. Besides providing
the host interface the Vinculum also handles the FAT File System through upgradeable firmware in flash
memory. This allows the user to access files on the drive using simple serial commands without having
to deal with drive or file structure. Files are in standard FAT format and can be read and written from a
PC as well providing excellent portability of the data and files. By formatting the output of the data going
to the drive, files can be saved that can be imported directly into applications, such as spreadsheets,
where the data can be plotted or graphed.
Command Set
The command set for the Memory Stick Datalogger is contained within the Vinculum Firmware
Specifications on the Datalogger product page (link above).
Please see the section on Firmware
Command Set. This sheet provides complete details of the command set used by this module as well as
responses from the module.
There is both a full verbose (DOS Style) command set as well as a
condensed command set with less verbose responses which can make it easier on the BASIC Stamp
Modules. FAT12, FAT16 and FAT32 formats are supported.
Precautions
Some USB drives may not properly initialize when connected to the Datalogger. If the light on your drive
stays on when connected or if it doesn’t blink, try removing and reconnecting the drive.
Removing or powering down a USB Drive while data is being written to it can corrupt both the data and
the file system of the drive. Be sure the drive is not being written to when you disconnect or power off
the Datalogger or Drive. Be sure that your program closes files that it opens for writing. Not closing
these files can also cause corrupt data. A crashed program can also cause this if it never closes the file
and the drive is shut down or removed.
If you continue having trouble reading from or writing to your USB drive, try the following.
Connect the USB drive to your PC. Open a My Computer window so you can see what drive letter was
assigned to the drive. Open a command prompt (DOS) window and type the following (replacing x with
the letter assigned to your drive):
chkdsk x: /f
This will scan the drive for any file system errors and repair them. Always back up important data on the
drive before running chkdsk or even before logging any data to it to avoid losing important information.
Copyright © Parallax, Inc. • Memory Stick Datalogger (#27937) • v1.1
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