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IMPLEMENTING A SIMPLE USB INTERFACE

FOR AN EMBEDDED PROCESSOR

by Stuart Allman

Start ý Typical USB Solutions ý Required Components ý An Easier Solution ý Following the Rules ý Firmware ý Vendor-Specific Requests ý Host Transfer Mechanisms ý USB Transfers ý How Does It Work? ý The Grand Conclusion ý Sources and PDF

THE GRAND CONCLUSION

The embedded processor doesnýt have to know that youýve taken it off the old bus and put it onto a new one. This frees your embedded processor to handle your main system tasks and leave USB for the background. Plus, you can keep your same protocol if you are currently using RS-232.

Even moderate data throughputs for USB can make RS-232 solutions look old and tired. Itýs time to accept the fact that USB is here to stay and you may have to abandon your beloved RS-232 port.

The grand conclusion that I was trying to persuade you to come to is that the aspects of the USB can be hidden by the simple use of a USB microcontroller. If you treat the CY7C64013 microcontroller as a black box with data coming in and out of either end, then the design of an embedded system using USB becomes much simpler. Iýve given you the microcontroller firmware, USB host driver, USB host example and test application, and example firmware for multiple embedded processors. What excuse could you possibly have for not giving it a try in your next design?

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