USB drive, disk storage, mass storage nonUSB, non-USB
MSTOR - USB (Thumb) drive Interface for non-USB systems
by Versalent
MSTOR - Mass Storage Adapter -- a low-cost, small USB host adapter with an embedded disk file system that brings USB thumb drives to any non-USB system through a UART or I2C.     A simple command set lets you create and modify files and navigate and manage a directory structure, and even provides optional encryption. Timestamps are automatically managed and files can be read/written/modified/encrypted easily. The FAT file system is PC compatible! A companion configuration program allows you to set baud rates, I2C address, control encryption with your own unique encryption key, set read/write timeouts etc. Disk data is transferred in blocks that are CRC'd to verify data integrity. For flexibility, connection is via DB9 connector, or flat cable connector or screw terminals. MSTOR IMAGE
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MSTOR Datasheet by Versalent

MSTOR    USB drive interface for microcontrollers

  • Provides interface to standard USB drives, FAT formatted, PC compatible
  • Provides multiple microcontroller communication interfaces (RS232/485/I2C)
  • Can be 'hot-swapped' during idle times
  • Can encrypt/decrypt files using your own 128-bit (16 character) AES key
  • Battery backed real-time clock(1+ year life)
  • Low cost and small: 4.2" X 3.2" X 0.9"
  • DB9 connector and screw terminal connections, optional 14-pin flat ribbon cable connector


  • Small systems without USB needing large/removal storage
  • nonUSB systems requiring data transfer to/from a PC
  • Small systems requiring remote/physically protected or encrypted storage

       MSTOR is a small module/adapter that brings up to 32 gig of standard mass storage to small computer systems that do not have a USB port. The file system allows a user to send simple commands to List Files and Directories, Read/Write/Erase Files, Make/Delete Directories, manage encryption, and more ... to a USB drive without any FAT file system coding. A companion program for Windows PCs is provided to configure MSTOR and exercise all its features. For close proximity to your system, the I2C interface can be used -- for more than a few feet distant there are RS232/485 interfaces available. Full manual here

User Selectable

  • Interface .. I2C/RS232/RS485
  • Disk Location .. Externally Accessible
MSTOR is available with the following options:
  • 5 VDC input or 6-12VDC input
  • DB9 connector for RS232 signals (RS232 signals also available on screw-terminals, and Ribbon Cable header)
  • Optional 14-pin Ribbon Cable header
ModelDescription (All with Screw-Terminals)
MSTOR-5DSMSTOR 5VDC w/DB9 and screw terminals
MSTOR-5DSRMSTOR 5VDC w/DB9, screw terminals, and 14-pin IDC (ribbon cable) connector
MSTOR-VDSMSTOR 6-12VDC w/DB9, screw terminals and 2.1mm power jack
MSTOR-VDSRMSTOR 6-12VDC w/DB9, screw terminals, 14-pin ribbon cable connector, and 2.1mm power jack
User Selectable Interfaces Available on All Models
Interface TypeDescriptionTransfer Speed Typical
I2CIndustry Std. 2-wire, very short distance (< 4 feet) ~25kbyte/sec(400kHz CLK)
RS232/485Industry Std. 3-wire, long distance (> 100 feet) ~8kbyte/sec(@115kBaud)
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USB drive, disk storage, mass storage nonUSB, non-USB