Andy is right, there is also a Texas Instruments 8052-based MCU that includes full 8052 support. It's the TUSB2136 which includes an integrated USB hub. I believe there is another one called the TUSB3120 that doesn't include the hub.

I wrote keyboard firmware for a USB keyboard based on the TUSB2136. It wasn't too tricky in 'C', although the same code would've been a little messy in assembly. Certainly "do-able" though. But it was one of the few times I was glad the customer didn't request the development be done in assembly. :)

I believe the TI parts mentioned above and the various parts offered by Cypress are the 8052 solutions to USB connectivity. If you already have 8052 development tools and experience it's a neat way to get USB without any new investments. Books that discuss Cypress USB connectivity are surprisingly applicable to the TI parts, by the way. I recommend "USB Complete" by Axelson and "USB Design by Example" by Hyde.

I don't know about the price of the Cypress parts, but the cost of the TI parts is quite attractive.

Regards,
Craig Steiner