Cypress 2100 manual Enumeration ReNumeration, How It Works

EZ-USB Series 2100

Enumeration and

ReNumeration

Anchor Chips’ proprietary ReNumeration™ function is the means by which the enhanced 8051 firmware is downloaded.

How It Works

Upon power-up or plug-in, the EZ-USB chip automatically enumerates as a default USB device. This allows the USB core

to download 8051 code. The USB core logic inside EZ-USB per- forms this initial enumeration and code download while holding the 8051 in reset.

Once enumerated, the host PC downloads 8051 code into EZ-USB RAM over the USB interface. (Anchor Chips supplies the software tools to incorporate the loader into any application). The downloaded 8051 code contains program, data, and

enumeration tables. Once loaded, the EZ-USB core performs a ReNumeration cycle to simulate a USB disconnect and reconnect to come back as a completely new USB device.

This entire sequence of enumera- tion, download and ReNum- eration happens quickly (less than a quarter of a second) and is transparent to the user.