Hi guys,

I have a complex .op with control of a number of switches and component values on a simple selection for a parameter CTRL which can be 1, 2, 3 or 4. I'm doing this with statements like:

.param V1=table(CTRL, 1, 0V, 2, 0V, 3, 5V, 4, 5V)

to switch for, for example, CTRL==(1 OR 2) or (3 OR 4). (Yes it simplifies but there are other combinations elsewhere.) I would like to include another parameter say BST as 0 or 1 to that. It currently means that I have to do the following:

.param V1=table(CTRL, 1, 0V, 2, 0V, 3, 5V, 4, 5V, 5, 5V, 6, 0V, 7, 5V, 8, 0V)

I now need 8 values to represent all of the possible combinations. Of course it is sensible that I should simply act on a logical combination of the two parameters using something like AND(CTRL==1, BST==0). Is there any way this is possible in LTSpice?

I have read the manual and can't find anything, likewise I've spent a day looking on the internet and can find advanced and undocumented procedures and functions but nothing that seems to touch on this.

 

As long as parameters are defined before RUN, LTspice can resolve logical combinations of them.
For example, if you have the directive ".params a=1 b=1 c=0 d=1", then a behavioural voltage source with output V=(a&b)|(c&d) will give the appropriate "1" out.

 

Wonderful! Thanks Alec that is exactly the answer I was looking for. I should have thought to try the simple "&" and "|" symbology but I was convinced it would be more textual so couldn't get past "AND" and "OR". It's working beautifully now with setting my 2 variables and selecting combinations of the two as I need. Thank you.

 

Glad you got it working.