MANUAL FOR FPGAIT (BBC BASIC & 6502 ASSEMBLER)

This file describes the program FPGAIT which transfers bit files for the
Xilinx XC4000 series of field programmable gate arrays from a disk over to the
device being programmed.
The manual and software are (C)2000 SPROW

INSTRUCTIONS-
At the BASIC prompt,type CHAIN"FPGAIT"

Enter the path and filename of the ".bit" file produced by the Xilinx FPGA
compiler software,this file will then be opened and a summary of statistics
displayed which are extracted from the ".bit" file.

The software will then serialise the image out of some pins on the user port
then start the FPGA design.If all is well it will report 
 "Image sent,chip has started"
when it has finished.

Note that due to the limited memory on the BBC micro the software fetches
chunks of 16k,so the disk drive will start and stop periodically during the
transfer process.

KNOWN PROBLEMS/FUTURE ENHANCEMENTS-
No known problems

EXIT MESSAGES-
"Programming failed" - the nDONE pin changed state which usually means the
                       FPGA has found a bit error resulting in the CRC failing
"DONE changed while not programming" - the FPGA has changed state without the
                       software doing anything.Power off/on the FPGA board
"File not found" - the given bit file is not on the disk
"Missing token" - bit files consist of a series of tokens,and one was missing
                  probably due to a corrupted bit file
"No data length token" - the length token following a token was missing 
                         probably due to a corrupted bit file

HISTORY-
V0.33 First public version to support the FPGA workshop