PDP era and a question

From: Eric Smith <eric_at_brouhaha.com>
Date: Sun Aug 29 20:45:24 1999

Tony wrote:
> There is another reason I want this information. I want to create
> self-modifying circuits, reconfigurable CPUs, etc. And I can't do that if
> I am forced to use the manufacturers tools for every change in configuration.

Most FPGAs can't be used in that manner in a practical fasion anyhow.
Normally you have to put the FPGA into a special programming mode, during
which it loads its configuriation and is otherwise non-functional. The
closest you could get to self-modifying is to have an FPGA configuration that
computes a new configuration, writes it to external RAM, and then resets
itself (forcing a reconfiguration). This would almost certainly require
at least a small amount of external dedicated logic to select which
configuration memory to use and to control the timing of the update.

There was a line of FPGAs specifically designed for reconfigurable
computing; it divided up the FPGA into sections and allowed reconfiguration
at section granularity. I think it was made by either Actel or Atmel.
Received on Sun Aug 29 1999 - 20:45:24 BST