Revision 1.2

June 1, 2001

-3-

GL641USB

GL641USB

GL641USB

GL641USB

2. Functional Overview

The GL641USB is a USB storage class controller that supports ATA/ATAPI/Compact Flash device. It is compliant to

USB 12Mbps protocol and data transfer rate is up to 1.1Mbytes/Sec. It is also compliant to USB Storage Class Bulk

Only protocol. There are 4 endpoints in GL641USB controller. Endpoint 0 is a Control endpoint for this controller. It

is used to initialize this USB device. Endpoint 1 is a Bulk IN endpoint. It is used to read data from the storage device.

Endpoint 2 is a Bulk OUT endpoint. It is used to issue SCSI packet command to the storage device and write data to

the storage device. Endpoint 3 is an Interrupt IN endpoint and not used by USB Storage Class Bulk Only protocol

currently.

Micro-

controller

USB

Registers

&

FIFO

Control

Endpoint 0

Control

8 Bytes FIFO

Endpoint 1

Bulk IN

64 Bytes FIFO

USB

Interface

D+

D-

Endpoint 2

Bulk OUT

64 Bytes FIFO

Endpoint 3

Interrupt IN

8 Bytes FIFO

ATA

ATAPI

CF

Interface

ATA

Figure 2-1 Block Diagram of GL641USB