Content for 74HC157

74HC157

The 74HC157; 74HCT157 is a high-speed Si-gate CMOS device and is pin compatible with Low-power Schottky TTL. It is specified in compliance with JEDEC standard no. 7A. The 74HC/HCT157 are quad 2-input multiplexers which select 4 bits of data from two sources under the control of a common data select input (S). The enable input (E) is active LOW. When E is HIGH, all of the outputs (1Y to 4Y) are forced LOW regardless of all other input conditions. Moving the data from two groups of registers to four common output buses is a common use of the 74HC/HCT157. The state of the common data select input (S) determines the particular register from which the data comes. It can also be used as function generator. The device is useful for implementing highly irregular logic by generating any four of the 16 different functions of two variables with one variable common. The 74HC/HCT157 is logic implementation of a 4-pole, 2-position switch, where the position of the switch is determined by the logic levels applied to S.

MK1 8bit Computer

“The MK1 CPU is composed of several modules, all connected trough a common 8-bit BUS, the status of each module is shown by dedicated LEDs. The clock module is designed to allow step-by-step execution; in automatic mode the clock speed …

The Amethyst Colour Video System

“The Amethyst is a retro-styled “home computer” built around an Atmel ATmega1284 microcontroller. It features composite (NTSC) video output with both high-color and high-resolution modes, mono audio output, and a full-travel mechanical keyboard. It includes a full-featured implementation of the …

A digital quartz clock from scratch

“After 20+ years of programming, I wanted to get some understanding of the electronics that make my career possible. I had built the basic individual logic gates with transistors on a breadboard, but to build anything meaningful I needed loads …

GBA Bluetooth HID

“Turn your Game Boy Advance into a Bluetooth Controller :) How to use it: After launching the rom the bluetooth module enters discoverable mode. This means you can pair to it from whatever device you are going to use it with …

ATtiny84/85 SPI Interface Pin Reuse

“This instructable is a follow up to the “ATtiny84/85 In-circuit Debugging with Serial Output” instructable and extends that hardware and software configuration to address the issue of reuse of the programming download pins by the application program. Altogether, between …

Arduino Altair 8800 simulator

“For a long time I have thought it would be cool to have an Altair 8800 computer to play around with. But working vintage Altairs are rare and therefore expensive, easily costing $1500-$2500 if available at all. There are …