IC tester part 1:

This article describes a stand-alone IC tester for logic ICs (with up to 24 pins) from the well-known 74xx (TTL) and 40xx (CMOS) series. The elementary building blocks that make up the design are an 80C535 microcontroller, a large EPROM, an LCD display, a small keyboard and an RS232 interface. In this first instalment, our main subjects will be hardware-related.