ISD-200 Datasheet, PDF (19/64 Pages) List of Unclassifed Manufacturers – USB Mass Storage Class Bulk-Only Specification Compliant

ISD-200 ASIC Datasheet
Descriptor Override
If the ISD-200 is to be used in applications where either ATA or ATAPI devices may be connected, the
Descriptor Override configuration bit must be set. To avoid confusion, it is suggested that the
idProduct(LSB) descriptor field be assigned an even or odd value depending on the device type. The
detection of an ATA or ATAPI device initialization failure results in bit-0 of this value being replaced with
‘1’. Thus, it is suggested that ATAPI devices should have even idProduct values and ATA devices odd.
Pipes
This ISD-200 provides four USB pipes: Default Control, Bulk Out, Bulk In, and Interrupt.
Default Control Pipe
The default pipe is used to transport standard, class and vendor-specific USB requests to the ISD-200.
Bulk Out Pipe
The Bulk Out pipe is used to send command and data to an attached mass storage device. Maximum
packet size is 64 bytes.
Bulk In Pipe
The Bulk In pipe is used to receive status and read data from an attached mass storage device. Maximum
packet size is 64 bytes.
Interrupt Pipe
The Interrupt pipe is implemented for legacy driver compatibility reasons only. If addressed, it will always
return 0x00.
Requests
The ISD-200 responds to three different types of request:
• Standard USB device requests
• Mass Storage Class Bulk-Only requests
• Vendor-specific requests
Standard Requests
The ISD-200 supports all USB standard device requests except the optional Set Descriptor request. These
requests, which are described in Chapter 9, Device Framework, of the USB Specification, are:
• Clear Feature
• Get Configuration
• Get Descriptor (for information on String Descriptors, see String Descriptors on page 23)
• Get Interface
• Get Status
• Set Address
• Set Configuration
• Set Interface
• Set Feature
Mass Storage Class Bulk-Only Requests
Mass Storage Class Bulk-Only requests supported by the ISD-200 are listed in the following table.
In-System Design Confidential
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