HID code
using frameworks for the EZ-USB

This is the readme file for fwhid.zip. Fwhid is HID firmware for Cypress Semiconductors' EZ-USB chip. The code is based on Cypress' frameworks C code and is available from Lakeview Research at http://www.lvr.com.

I developed the firmware using Keil's C compiler and uVision V1.32. The firmware is an adaptation of Cypress' bulktest example. The code requires the full (not evaluation) version of the C compiler.

The firmware defines the device as a member of the human-interface device (HID) class. It enables the device to send and receive 2 bytes of generic data. The code works with the usbhidio application available from www.lvr.com.

These are the major changes I made to the bulktest code:

• In dscr.a51, the class in the interface descriptor is HID, and I added a HID descriptor, a report descriptor, and two interrupt endpoint descriptors.
• In fw.c, I added code to enable the host to retrieve the report descriptor.
• In periph.c, I adapted the code to enable the HID endpoints to send and receive data.
• Dscr.h and ezsub.h have additions required for the above changes.

I left the rest of the code intact, even though some of it (such as code for the other endpoints) is unused.

I surrounded each change or addition to the code with the following comments:

To avoid problems with paths, I recommend copying the program files to a new folder in the same location used for the other EZ-USB examples. (The default is Anchor\EzUsb\Examples).

Limitations

This version of the code has limitations that I hope to eliminate eventually:

• The host must be running Win98SE , Win2K, or later. This is because the code uses interrupt transfers for both In and Out reports. Windows 98 gold (original) supports only HID 1.0 and thus uses control transfers for Out reports.
• The code supports only one report (report 0).
• The code doesn't support Feature reports.

I welcome whatever comments, bug reports, fixes (especially fixes!), critiques, suggestions, etc. that you may have about this code. Contact me at jan@Lvr.com

I have much more information and example code for HID-class devices and other topics for USB developers on my USB page:

http://www.lvr.com/usb.htm

Jan Axelson

Lakeview Research