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USB to IDE enclosure chipset benchmarks

The main thing to consider in USB enclosure performance, is the chipset used. In this article we will be looking at different enclosures that represent the main chipsets on the market today.

This includes the following chipsets:
Cypress EZ-USB AT2L
Prolific PL-2507
ALi M5621
Genesis Logic GL811E

Here is the EZ-USB AT2LP from Cypress Semiconductor. The chip is labeled CY7C68300B.

From the Cypress Semiconductor website:



    *Fixed-function mass storage device-requires no firmware code
    *Two power modes: Self-powered and USB bus-powered to enable bus powered CF readers and truly portable USB hard drives
    *Certified compliant for USB 2.0 (TID# 40460273), the USB Mass Storage Class, and the USB Mass Storage Class Bulk-Only Transport (BOT) Specification
    *Operates at high (480-Mbps) or full (12-Mbps) speed USB
    *Complies with ATA/ATAPI-6 specification
    *Supports 48-bit addressing for large hard drives
    *Supports ATA security features
    *Supports all ATA commands via ATACB function
    *Supports mode page 5 for BIOS boot support
    *Supports ATAPI serial number VPD page retrieval for Digital Rights Management (DRM) compatibility
    *Supports PIO modes 0, 3, 4, multiword DMA mode 2, and UDMA modes 2, 3, 4
    *Uses one external serial EEPROM for storage of USB descriptors and device configuration data
    *ATA interface IRQ signal support
    *Support for one or two ATA/ATAPI devices
    *Support for CompactFlash and one ATA/ATAPI device
    *Can place the ATA interface in high-impedance (Hi-Z) to allow sharing of the ATA bus with another controller (e.g., an IEEE-1394 to ATA bridge chip or MP3 Decoder)
    *Support for board-level manufacturing test via USB interface
    *Low-power 3.3V operation
    *Fully compatible with native USB mass storage class drivers
    *Cypress mass storage class drivers available for Windows
      (98SE, ME, 2000, XP) and Mac OS X

Functional Description

The EZ-USB AT2L(TM) CY7C68300B/CY7C68301B and CY7C68320/CY7C68321) implements a fixed function bridge between one USB port and one or two ATA- or ATAPI-based mass storage device ports. This bridge adheres to the Mass Storage Class Bulk-Only Transport Specification and is intended for bus- and self-powered devices.