Content for 74HCT139


The 74HC139; 74HCT139 decodes two binary weighted address inputs (nA0, nA1) to four mutually exclusive outputs (nY0 to nY3). Each decoder features an enable input (nE). When nE is HIGH all outputs are forced HIGH. The enable input can be used as the data input for a 1-to-4 demultiplexer application. Inputs include clamp diodes. This enables the use of current limiting resistors to interface inputs to voltages in excess of VCC.

CSCvon8: 8-bit von Neumann Crazy Small CPU

“This repository holds the files for my 8-bit “big brother” CPU to the 4-bit Crazy Small CPU. This is a von Neumann style CPU designed with 7400-style logic chips and some RAM and ROM. The CPU requires only seventeen chips …

6502 retro controller board

“Classic CPU as an “Arduino style” microcontroller An attempt to create “Adruino inspired” set of modular boards, containing thirty years old parts - primarily vintage 6502 microprocessor. About one year ago I noticed that some sellers on popular Chinese auction site …