usb_jtag using Cypress FX2 chip===============================The code in this directory is for Cypress FX2 (e.g. CY7C68013A) and can be compiled withthe SDCC compiler (I tried version 2.6 as shipped with Ubuntu 6.10). Once I had a versionthat could be compiled with Keil tools (until early 2007), but switched to SDCC because I usually develop on a Linux host.No logic beside the FX2 itself and only a few external components are required for a basicJTAG adapter. I don't have detailed schematics available; my test setup consists of a FX2on a custom board where it's directly connected to a Cyclone FPGA.        ____________       |            |       | Cypress    |  USB__| EZ-USB FX2 |__JTAG(TDI,TDO,TCK,TMS)       | CY7C68013A |       |____________|        __|__________       |             |       | 24 MHz XTAL |       |_____________|Similar eval boards are now available from fpga4fun.com - the boards named"Saxo-L" and "Xylo-EM" are pre-wired for use with an adapted version of mycode, while "Saxo" and "Xylo" can be used after soldering 4 extra wires:	http://www.fpga4fun.com/board_Xylo.htmlAs is, the code assumes the following pin assignment: Port C.0: TDI Port C.1: TDO Port C.2: TCK Port C.3: TMSOther assignments are possible; you'll have to adapt the definitions in hardware.h and maybein hardware.c, too.The USB identification data (vendor/product ID, strings, ...) can be modified in dscr.a51. Myfirmware emulates the 128 byte EEPROM that usually holds configuration data for the FT245 andwhich can be read from the host; its content is computed from the data in dscr.a51 as well.The WAKEUP pin should be high for the re-numeration to work reliably (thanks Jean/fpga4fun!)From this release on, there is new code to support running in the "XilinxPlatform Cable USB". If you select HARDWARE=hw_xpcu_i or hw_xpcu_x at the topof the Makefile, a firmware for the XPCU will be built. I've tested this onlywith unmodified CPLD version 18 (0x12) on a Spartan-3E starter kit, as it wasprogrammed by my WebPack 8.2i. The code needs optimization; yet it is merely aproof of concept. hw_xpcu_i: Access "internal" chain (the XPCU CPLD, IC3, itself) hw_xpcu_x: Access "external" chain (the Spartan 3E, PROM, etc.)Changes since previous release on 2007-01-28:  - Initial suppport for running on Xilinx XPCU.  - New FX2 code, based on USRP2 from the GNU Radio Project;  - Firmware can now be compiled using SDCC 2.6. No more Keil support.  - EEPROM content is automatically computed from descriptors, including checksum.Changes since initial release on 2006-04-23:  - added this readme.txt  - reorganized my project folder: diff is now created from Subversion repository  - stripped *.dist extension from eeprom.c and dscr.a51   - added unique proper product and vendor ID (thanks to Antti Lukats!)  - fixed checksum in eeprom.c  - added comments about AS/PS mode pins in usbjtag.c