[Hardware] FPGAs

Herbert König herbertkoenig at gmx.net
Mon Aug 13 10:52:00 UTC 2007

Hello Jecel,

thank you for the overview.

JAJ> The Erasable PROM (EPROM) allowed you to reuse the same device since you
JAJ> could expose it to ultraviolet light to reset it to the blank state.
JAJ> These devices were larger and slower than PROMs. The only example I know
JAJ> of an EPROM being use as logic was for the video signals generator on my
JAJ> own Merlin 2 design.

I can add two examples:

-at Vuko we used an EPROM as a character generator too. The EPROM was
driving DA converters to paint the characters on a CRT which otherwise
was a digital oscilloscope. I thought of this as a common design for
the earlier digital oscilloscopes. Was in about 1982. They sold some
thousand units.

More uncommon I used an EPROM as the logic control unit for a four
channel digital oscilloscope. Every logical expression was written in
FORTH like "trigger_occurred channel3 and add_ch3_and_ch4 and ...."
Then overnight a counter ran over all adresses of the EPROM, the
counter was decomposed into the logical functions which where all run
and the result was put into the EPROM at the address of the counter.

It was about 1985 and Vuko also sold a few thousand of these.

FORTH was nice for this, computer was a 6502 32K ram.


Herbert                            mailto:herbertkoenig at gmx.net

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