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Old 11-25-2007, 02:01 AM
Jim Granville
Posts: n/a
Default Re: using fpga as programmable connection

joe wrote:
> hi,
> i would like to use a small fpga (or cpld) on a pcb to make direct
> bidirectional connections between pins.
> basically it should act like a programmable "cable".
> is this kind of application possible using programmable logic?
> regards
> j

If you are looking for analog-switch crosspoint operation, no.
You will need direction control signals, and then you can
build a digital buffered crosspoint system.

How many nodes and what delays can you tolerate ?

A 128MC device could get close to 16x16 crosspoint.

Some CPLDs are RAM based, loaded at power up, and those
variants can be RAM reloaded - meaning you could re-spin the
logic itself, via the JED info, in order to get
maximum crosspoint choice, in a small device.
Makes more sense in higher volume apps, as there is more engineering


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