wfjm.w11

The usb_jtag sub project was checked out on 2011-07-17 (Rev 204) from Sourceforge and taken as basis for the further developement. The original README.txt is preserved under README_iso_jtag.txt. Only the hw_nexys.c branch was kept on the import.

Change log:

2014-11-16 (Rev 604)

ported to sdcc 3.3
- all prior development was done with sdcc 2.x, latest sdcc 2.9 was bundled with Ubuntu 12.04 LTS.
- now switching to sdcc 3.3 as bundled with Ubuntu 14.04 LTS.
- mayor changes:
  - assembler now named sdas8051 (was asx8051)
  - all special reserved keywords start now with a double underscore
```
  at        --> __at
  bit       --> __bit
  interrupt --> __interrupt
  sbit      --> __sbit
  sfr       --> __sfr
  xdata     --> __xdata
  _asm      --> __asm
  _endasm   --> __endasm
  _naked    --> __naked
```
  - in general sources stayed untouched in the sdcc 2.9 form, all keyword mappings are done with the preprocessor and defs like -Dat=__at
  - make usage now
    - default is now sdcc 3.x, in this case simply use
```
 make clean && make
```
    - on systems with sdcc 2.x use
```
 make clean && make SDCC29=1
```
- detected and fixed BUG inherted from ixo-jtag and GNU Radio in SYNCDELAY The macro SYNCDELAY (defined in lib/syncdelay.h) inserts 'nop' needed to resolve some timing issues in the FX2. The old implementation was
```
  #define SYNCDELAY _asm nop; nop; nop; _endasm
  #define NOP       _asm nop; _endasm
```
  This inserts into the assembler output a single line
```
  nop; nop; nop;
```
  Since ';' is the comment delimiter for the assember the 2nd and 3rd nop are simply ignored.
  
  This wrong implementation was changed to
```
  #define SYNCDELAY   NOP; NOP; NOP
```
  That created three lines in the assembler output
```
  nop;
  nop;
  nop;
```
  and generated the three desired nops in the binary.
  
  This was definitively broken from the very beginning.
  The code ran alway. Reason is mosu likely that the SYNCDELAY
  macros were only used in the setup phase and never is a
  really time critical context.

2011-07-17 (Rev 395)

Makefile: reorganized to support multiple target/fifo configs

renames:

  dscr.a51   -> dscr_jtag.a51
  hw_nexys.c -> hw_nexys2.c
  usbjtag.c  -> main.c

dscr_jtag.a51
- Use USB 2.0; New string values
- use 512 byte for all high speed endpoints
dscr_jtag_2fifo.a51
- dscr with EP4 as HOST->FPGA and EP6 as FPGA->HOST hardware fifo