CY7C68300B/CY7C68301B
CY7C68320/CY7C68321
Document 38-08033 Rev. *D
Page 2 of 36
3.0
Applications
The CY7C68300B/301B and CY7C68320/321 implement a
USB 2.0 bridge for all ATA/ATAPI-6 compliant mass storage
devices, such as the following.
• Hard drives
• CD-ROM, CD-R/W
• DVD-ROM, DVD-RAM, DVD+/–R/W
• MP3 players
• Personal media players
• CompactFlash
• Microdrives
• Tape drives
• Personal video recorders
The CY7C68300B/301B and CY7C68320/321 support one or
two devices in the following configurations.
• ATA/ATAPI master only
• ATA/ATAPI slave only
• ATA/ATAPI master and slave
• CompactFlash only
• ATA/ATAPI slave and CompactFlash or other removable
IDE master
3.1
Additional Resources
• CY4615B EZ-USB AT2LP Reference Design Kit
• USB Specification version 2.0
• ATA Specification T13/1410D Rev 3B
• USB Mass Storage Class Bulk Only Transport Specification,
www.usb.org
4.0
Introduction
The EZ-USB AT2LP
™ (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.
The AT2LP is the latest addition to the Cypress USB mass
storage portfolio, and is an ideal cost- and power-reduction
path for designs that previously used the ISD-300A1, ISD-
300LP, or EZ-USB AT2.
Specifically, the CY7C68300B/CY7C68301B includes a
mode that makes it pin-for-pin compatible with the EZ-
USB AT2 (CY7C68300A).
The USB port of the CY7C68300B/301B and CY7C68320/321
(AT2LP) are connected to a host computer directly or via the
downstream port of a USB hub. Host software issues
commands and data to the AT2LP and receives status and
data from the AT2LP using standard USB protocol.
The ATA/ATAPI port of the AT2LP is connected to one or two
mass storage devices. A 4-Kbyte buffer maximizes ATA/ATAPI
data transfer rates by minimizing losses due to device seek
times. The ATA interface supports ATA PIO modes 0, 3, and 4,
multiword DMA mode 2 and Ultra DMA modes 2, 3, and 4.
The device initialization process is configurable, enabling the
AT2LP to initialize ATA/ATAPI devices without software inter-
vention.
5.0
68300A Compatibility
The CY7C68300B/301B and CY7C68320/321 are available in
three package types that are pictured in the following sections.
As mentioned above, the CY7C68300B/301B contains a
backward
compatibility
mode
that
allows
the
CY7C68300B/301B to be used in existing EZ-USB AT2
(CY7C68300A) designs. Please refer to the logic flow below
for more information on the pinout selection process.
Read EEPROM
EEPROM
Signature
0x4D4D?
Yes
Set
EZ-USB AT2
(CY7C68300A)
Pinout
Set
EZ-USB AT2LP
(CY7C68300B)
Pinout
No
Normal Operation
Figure 5-1. Simplified Startup Flowchart (68300B only)
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