Parallel Port Logic Analyzer

When you build a digital electronic project and have trouble with it you need a device to debug it. To analyze logic output from your project you need a Logic Analyzer. 
If you don’t have it you can try to build by yourself cheap logic analyzer device using parallel port. The device only use few resistors and IC 74HC245 as data buffer. To display the graphical output from logic analyzer device you can use Fabulous Logic Analyzer software, here.


Schematic:

Parallel Port logic analyzer

Component Required:
IC1,               74HC245
R1-R8,         10K ohm
R9-R16,       100 ohm
R17,              2K ohm
LED
DB25 Male, Parallel Port Connector