Cypress CY7C68301C Manual De Usuario
CY7C68300C/CY7C68301C
CY7C68320C/CY7C68321C
CY7C68320C/CY7C68321C
Document 001-05809 Rev. *A
Page 2 of 42
Applications
The CY7C68300C/301C and CY7C68320C/321A implement
a USB 2.0 bridge for all ATA/ATAPI-6 compliant mass storage
devices, such as the following:
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 CY7C68300C/301C and CY7C68320C/321A support one
or two devices in the following configurations:
or two devices in the following configurations:
• ATA/ATAPI master only
• ATA/ATAPI slave only
• ATA/ATAPI master and ATA/ATAPI slave
• CompactFlash only
• ATA/ATAPI slave and CompactFlash or other removable
IDE master
Additional Resources
• CY4615C 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
Introduction
The EZ-USB AT2LP
™ (CY7C68300C/CY7C68301C and
CY7C68320C/CY7C68321C) 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
(BOT) and is intended for bus- and self-powered devices.
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
(BOT) 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 Cypress’s ISD-300A1,
ISD-300LP, or EZ-USB AT2.
storage portfolio, and is an ideal cost- and power-reduction
path for designs that previously used Cypress’s ISD-300A1,
ISD-300LP, or EZ-USB AT2.
Specifically, the CY7C68300C/CY7C68301C includes a
mode that makes it pin-for-pin compatible with the
EZ-USB AT2 (CY7C68300A).
mode that makes it pin-for-pin compatible with the
EZ-USB AT2 (CY7C68300A).
The USB port of the CY7C68300C/301C and
CY7C68320C/321A (AT2LP) are connected to a host
computer directly or with the downstream port of a USB hub.
Software on the USB host system issues commands and
sends data to the AT2LP and receives status and data from
the AT2LP using standard USB protocol.
CY7C68320C/321A (AT2LP) are connected to a host
computer directly or with the downstream port of a USB hub.
Software on the USB host system issues commands and
sends 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 KB buffer maximizes ATA/ATAPI
mass storage devices. A 4 KB 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.
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.
AT2LP to initialize ATA/ATAPI devices without software inter-
vention.
CY7C68300A Compatibility
As mentioned above, the CY7C68300C/301C contains a
backward compatibility mode that allows it to be used in
existing EZ-USB AT2 (CY7C68300A) designs. The backward
compatibility mode is enabled by programming the EEPROM
with the CY7C68300A signature.
backward compatibility mode that allows it to be used in
existing EZ-USB AT2 (CY7C68300A) designs. The backward
compatibility mode is enabled by programming the EEPROM
with the CY7C68300A signature.
During startup, the AT2LP checks the I
2
C™ bus for an
EEPROM with a valid signature in the first two bytes. If the
signature is 0x4D4D, the AT2LP configures itself for pin-to-pin
compatibility with the AT2 and begins normal mass storage
operation. If the signature is 0x534B, the AT2LP configures
itself with the AT2LP pinout and begins normal mass storage
operation.
signature is 0x4D4D, the AT2LP configures itself for pin-to-pin
compatibility with the AT2 and begins normal mass storage
operation. If the signature is 0x534B, the AT2LP configures
itself with the AT2LP pinout and begins normal mass storage
operation.
Refer to the logic flow in
for more information on the
pinout selection process.
Most designs that use the AT2 can migrate to the AT2LP with
no changes to either the board layout or EEPROM data.
Cypress has published an application note focused on
migrating from the AT2 to the AT2LP to help expedite the
process. It can be downloaded from the Cypress website
(
no changes to either the board layout or EEPROM data.
Cypress has published an application note focused on
migrating from the AT2 to the AT2LP to help expedite the
process. It can be downloaded from the Cypress website
(
) or obtained through a Cypress
representative.
Figure 1. Simplified Pinout Selection Flowchart
Read EEPROM
EEPROM
Signature
Signature
0x4D4D?
Yes
Set
EZ-USB AT2
(CY7C68300A)
Pinout
Set
EZ-USB AT2LP
(CY7C68300B)
Pinout
No
Normal Operation