Hades logoHades applet banner
TTL-series 74181 ALU demonstration

applet icon

The image above shows a thumbnail of the interactive Java applet embedded into this page. Unfortunately, your browser is not Java-aware or Java is disabled in the browser preferences. To start the applet, please enable Java and reload this page. (You might have to restart the browser.)

Circuit Description

This applet demonstrates the TTL-series 4-bit 74181 arithmetic-logical unit. It takes 4-bit operands and a carry input and calculates one of 16 logical or 16 arithmetic functions. Two additional active-low outputs X (/propagate) and Y (/generate) allow to interface to the 74182 carry-lookahead generator IC for fast addition.

The M input selects whether the ALU should calculate logical functions (M=1) or arithmetic functions (M=0). In each mode, the four S3..S0 opcode inputs select one of the available operations; check the table in the applet schematics for the specific funtions selected by each opcode. For example, M=0 and S=(1001) select the normal binary addition including carry, Z=(A+B+Cin).

Print version | Run this demo in the Hades editor (via Java WebStart)
Usage | FAQ | About | License | Feedback | Tutorial (PDF) | Referenzkarte (PDF, in German)
Impressum http://tams.informatik.uni-hamburg.de/applets/hades/webdemos/20-arithmetic/50-74181/demo-74181-ALU.html