USB-BDI Firmware

Introduction

This Firmware is writen for a EZ-USB FX2LP CY7C68013A. The USB-BDI is a composite USB devices which two parts. Firstly it creates a virtual com port which allows to communicate with the MSP555's SCI1 serial interface. Secondly its possible to program and debug the MSP555 over USB with this device.

How to start

The main method of the program is in the file usbpdi_main.c. It contains the initialization of the different parts of the device and a endless loop. The loop calls the different methods to handle the packages of the different endpoints and toggles a LED.

USB Device Descriptor

When the USB is plugged in the operating System sends some different requests. First it sends a set address request. This request handles the CY7C68013A automatically. After that the Host sends a get descriptor request. The picture below gives a overview which descriptors are sent to the Host. The values of the descriptors can be found in the file usb_descriptors.a51 A Detailed description can be found under www.usb.org or in the book Axelson - Serial Port Complete.

Descriptors

Change Log

From 1.1 to 1.2:

• Bug with UART buffer data length solved

From 1.0 to 1.1:

• The device appears now as BDI for MPC555 and virtual com port if plugged in
• The BDI and UART path are now separated from each other
• Bit Rate of the SCI1 is now variable and not fixed on 9800bit anymore.
• MPC332 is not supported anymore
• USB1.1 and lower is not supported anymore

Author:

Tinner Marco, Pertschy Simon, Schlaepfer Stephan

Version:

1.1