Content for 74LS173


The ’173 and ’LS173A 4-bit registers include D-type flip-flops featuring totem-pole 3-state outputs capable of driving highly capacitive or relatively low-impedance loads. The high-impedance third state and increased high-logic-level drive provide these flip-flops with the capability of being connected directly to and driving the bus lines in a bus-organized system without need for interface or pull-up components. Up to 128 of the SN74173 or SN74LS173A outputs can be connected to a common bus and still drive two Series 54/74 or 54LS/74LS TTL normalized loads, respectively. Similarly, up to 49 of the SN54173 or SN54LS173A outputs can be connected to a common bus and drive one additional Series 54/74 or 54LS/74LS TTL normalized load, respectively. To minimize the possibility that two outputs will attempt to take a common bus to opposite logic levels, the output control circuitry is designed so that the average output disable times are shorter than the average output enable times.

Project  MikroLeo


“MikroLeo project files (schematic, PCB, assembler, emulator/debugger, circuit simulation file, documentation, example of programs etc). MikroLeo is a 4-bit microcomputer developed mainly for educational purposes and distributed for free under open-source licenses. 4-bit Didactic Microcomputer The project is in …

SAP-1 Processor Architecture

“A simple 8-bit micro-processor using mostly discrete logic chips. This project is mostly based on the 8-bit Breadboard computer by Ben Eater Banner Specs ~400 Hz Clock 8-bit Data Bus 16-bit Control Word 5 Microsteps per Instruction 16 byte RAM …

Build an 8-bit computer from scratch

“I built a programmable 8-bit computer from scratch on breadboards using only simple logic gates. I documented the whole project in a series of YouTube videos and on this web site. “