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A Truth Table is a small programmable logic device.


Description (From Recipaedia)

A programmable circuit that uses a user-entered truth table to determine value of the output for all possible combinations of the inputs. There are 4 inputs on all sides and one output at the back (to access the output element must be placed on a Wire-Through-Block). The truth table must be entered manually by tapping edit button while holding the item in hand. Truth table contains output values for all possible input value combinations. Can be placed on any vertical surface and rotated to desired orientation.


NOTES on description:

The Recipaedia's description has two omissions. First, the output signal is a standard digital signal - NOT an analog signal. So, the only values available for this output are '0' or '1'. Second, the Truth Table CAN be edited after it's placed, in the same fashion as the memory bank. Simply walk up close to it and center your view on the device. The edit icon will appear.

Crafting

It requires 5 copper ingots and 2 germanium crystals to craft Truth tables. You get 4 chips.

Truth Table Circuit

Connections

The 4 inputs are on the sides of the device and are standard digital signals. In1 is the side with one dot. In2 is the side with two dots, and so forth. The output is sent out the back so this device MUST be placed on a wire through block to be useful. All inputs and the output are standard digital signals.

Operation

The Truth Table is a generic programmable logic device with one output. It is essentially a very small memory bank and can be used in place of several discrete logic gates provided you only need the one output. Once it is programmed, the output will only turn on ('1') only for the input combinations that are programmed for it.

Programming it

Walk up to the device and keep it centered in your view. When you are close enough, the SNEAK button will change to an EDIT button (a pencil and paper). Press this to enter the edit mode. A simple chart will pop up. Notice the input designations at the top of the chart and the grid of '0's and '1's in the main part. These show all the possible combinations of inputs. Scroll through these and find the combination(s) which you want to activate the output. Tap on the check box on the right and see that a check mark is entered. This means that a '1' will be output for that particular combination. When you are done programming the device, exit by tapping OK.

The LINEAR button will allow you to enter all output value in one line, instead of checking off boxes. This must be a string of '0's and '1's, up to 16 digits.

Uses

It can be used in a simple 4-switch locking device with no extra parts needed.

It can replace a number of other logic gates to keep a circuit smaller.

History 

The truth Table was introduced in version 1.23.

Notes

  • Despite Recipaedia's description, Truth Table Circuits can be placed on horizontal surfaces too as for 1.29.
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