The FPGA code in the small XP device can not be
corrupted by runaway software. There is no internal
connection that connects the internal logic of the device
to the internal EEPROM. The only way to reprogram this
EEPROM is via the external JTAG connections.

Now if the FPGA configuration code were to be corrupted
by a cosmic ray, then you may have a doorstop. If the
machine in which the card is fitted will not boot (unlikely,
but possible), then the only option will be to remove the card.

Once removed, it's possible to power up the card using
the 5V supply from the machine itself or another 5V supply,
run ispLever on the repaired machine, and reprogram the
small FPGA via JTAG.


On 6/10/06, Dieter <[EMAIL PROTECTED]> wrote:
> may I suggest that the write protect pin be
> connected to a header, so a jumper plug can disable it?  That way, it can be
> manually protected against runaway software.

If the PROM contents are bad due to runaway software or whatever reason,
does the board become a doorstop, or is there a fail-safe method to
reprogram it?

Some mainboards have a fail-safe loader.
Some have two copies of the firmware, and you only flash one copy at a time.
Some turn into doorstops if the flash doesn't work.  :-(

The two copies method could be useful for a development board.
Wire the select pins to a toggle switch.  Easy way to safely test
new firmware, and quickly recover if it doesn't work.
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