rLogic: Affordable, Tiny, Universal Logic
Watch signals propagate through basic digital circuits. Emulate any two-input logic gate using just one rLogic board and one jumper.
To order rLogic+, the breadboard compatible variant, simply order normal rLogic. When the survey is sent out you will indicate which you would like.
rLogic is a basic breakout board for the Fairchild Semiconductor TinyLogic® series of Configurable Logic Gates, with an LED for watching signals and cleverly arranged header pins for simple conversion from gate to gate. Different from programmable logic, configurable logic is manually changed through rewiring using a simple shunt (AKA, a jumper), allowing you to easily and quickly morph a single pinkie sized board into any basic logic function you might need. rLogic requires no prior knowledge, but if knowledgeable of basic digital circuitry then you may jump right in with creating. If not, then a few minutes with rLogic boards will begin to teach you the basics of digital electronics.
A breadboard compatible variant is also available, it operates in the same fashion as normal rLogic except that a jumper wire must be used instead of a shunt. rLogic+ should be more education friendly as less wires are necessary to use it. Also, rLogic+ would be difficult to use without a breadboard, as it lacks two sets of input and power pins. No special steps are needed to order rLogic+, instead as you will choose which variant you want in the survey. They are the same price and come in the same amounts. A prototype is in the works, for now here’s the board layout.
Logic gates are the simplest block typically used in designing digital circuitry. The logic gates of agreed upon and defined outputs of a 1 or 0 based on a certain set of 2 or more 1s or 0s, except inverters and buffers (NOT and Buf) which take one input and invert it or do nothing, respectively . Having to design electronics entirely using transistors would be arbitrary as those transistors would often repeat into the combinations known as logic gates. rLogic is designed to be any logic gate so that circuits big and small can be constructed from the simplest reasonable unit. The following gates are typically designed with: AND, OR, NOT, and XOR; as well as their complements (Which produce the exact opposite output), NAND, NOR, Buffer, and XNOR. A truth table, which associates outputs with corresponding inputs and gates types is shown below.
How Does It Work?
Operation is very simple, there are two forms of the rLogic board (A and B). Each board is capable of emulating a certain set of logic gates, as shown in the above diagram. The TinyLogic chip itself is technically just a type of 3-input logic gate, creatively designed by engineers at Fairchild Semiconductor to allow for the simple configuration to any useful 2-input gate. The above diagram displays the jumper configurations that lead to certain gates. For example, a jumper across A and one of the PWR pins on an rLogic A board configures it to be an AND gate, while on an rLogic B board it’s configured to a NAND gate. Then the gate inputs will be whichever two inputs are not tied, in this case those are B and C. To produce a XOR or XNOR a jumper should be placed across one set of A and B, then C acts as one input and the other A/B set together act as the other input. The header pins are configured to avoid messy wiring on the user’s end, and while the circuits may look messy, rainbow jumper cables allow for easy management and circuits can be assembled in just a few minutes. Wiring mistakes are unlikely to do any harm as the resilient little logic chips seem to survive polarity mistakes.
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