[sdiy] IC solutions for implementing reconfigurable look up tables?

Spiros Makris spirosmakris92 at gmail.com
Sun Aug 2 11:44:08 CEST 2020

I am prototyping an application that is based around the concept of using
LUTs to calculate logic functions.
So far I have successfully demonstrated the concept using an atmega328 and
the computational delay is within "specs" (still quite vague). One of the
advantages is that this delay is constant regardless of function
complexity. However, introducing the user control hardware also adds a new
delay which, although small, is now variable.
While the concept will work fine for control signals with delays up to
100-200us, my goal is to extend the operation up to the audio range,
hopefully ~10-15khz. In that context, I think that the valuable delay will
manifest as noise in the output spectrum. Would that be noticeable? I have
no clue, yet.
So I was trying to think of ways to implement the LUT in dedicated
hardware. Ideally, a combinational logic circuit that will be addressed
directly by the inputs and output the saved value directly, without any
other control logic or sequence required. A second MCU that only does this
task and is controlled via interrupts and serial by a central MCU (which
will support the screen and controls) is one solution I can think of and it
is fairly cheap - however that requires programming two controllers.
I am not very familiar with the memory offerings in the market (never
really used one). Is there anything that I could use to implement the
above? I thought of using serial in - parallel out registers and a bunch of
multiplexers, but that needs quite a lot of PCB space and will be fairly
Any ideas would be greatly appreciated!
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