What is 27C256 EPROM?

What is 27C256 EPROM?

The Microchip Technology Inc. 27C256 is a CMOS 256K bit electrically Programmable Read Only Memory (EPROM). The device is organized as 32K words by 8 bits (32K bytes). Accessing individual bytes from an address transition or from power-up (chip enable pin going low) is accomplished in less than 90 ns.

How to generate programming voltages of 25V 21v and 21v?

The programming voltages of 25V, 21V and 12.5V are generated with the help of zener diodes ZD1, ZD2 and ZD3. IC1 is used to provide +5V regulated supply to the circuit. To begin with, first read the programming voltage written on the EPROM. Now insert the EPROM chip into the 24-pin ZIF socket and slide switch S2 as per EPROM.

Where can I find the Willem programmer?

Interestingly, many adapters have there! Another store you will find the Willem Programmer is Aliexpress.com which is part of Yahoo’s Alibaba Group.