Stand-Alone Eprom Programmer

With the price of very capacious EPROMs (Erasable Programmable Read Only Memories) down to the level of several tens of bytes to the penny, it is not surprising to see a growing interest in periph- eral-like apparatus to load user- defined data into these devices, which can be erased again by exposing the chip to ultra-violet light. In this article we will examine a stand-alone pro- grammer that has built-in intelli- gence to make it usable either autonomously (stand-alone) or as a peripheral device con- trolled from a standard RS232 port. The latter facility has two important consequences. Firstly, the use of the program- mer is not restricted to copying EPROMs, since downloading EPROM data in the computer makes it possible to alter bytes and then write them back to a new EPROM, or the original master device if this has been erased in the meantime. Sec- ondly, the programmer is a truly universal peripheral thanks to the standard RS232 interface. Most computers nowadays have an RS...