The programmer devices requiredfor programming theelectrically programmable readonlymemories (EPROMs) are generallyexpensive. Here is a low-cost circuit toprogram binary data into 2716 and Priyank Mudgal 2732 EPROMs.The circuit uses timer NE555 (IC2)wired as a monostable. When push-toonswitch S1 is pressed, IC2 generatesa 50ms pulse, which is given to the programpin 18 of the ZIF SOCKET throughswitch S2. EPROM is inserted into theZIF SOCKET for programming. LED1 to indicate the application of theprogramming pulse to the EPROM.Before applying the programming pulseto the EPROM, select the programmingvoltage (25V, 21V or 12.5V, as specifiedby the manufacturer) applied to pin 21of the ZIF SOCKET by using jumperJ1. The programming voltage required an EPROM is sometimes written onits body. The address and data for theEPROM (ZIF SOCKET) are set by usingDIP switches SW1 and SW2, respectively,whose pins are initially pulledhigh via 10-kilo-ohm resistors.The AC mains is stepped down bytransformer X1 to deliver 30V, 250 mAfrom the secondary. The secondaryoutput is rectified by diode D1 andfiltered by capacitor C1. The programmingvoltages of 25V, 21V and 12.5Vare generated with the help of zenerdiodes ZD1, ZD2 and ZD3. IC1 is usedto provide +5V regulated supply tothe circuit.To begin with, first read the programmingvoltage written on theEPROM. Now insert the EPROM chipinto the 24-pin ZIF socket and slideswitch S2 as per EPROM. Then connectthe power supply to provide regulated5V DC to the circuit. Select theprogramming voltage using jumper J1and set the programming address anddata value using switches SW1 andSW2, respectively. After providing therequired programming voltage, pressswitch S1 to program the data at thedesired address. Repeat this procedurefor the next address and corresponding data.

Download full report
http://kitsnsparesadmin/pdffiles/Manual%20Eprom%20Programmer.pdf