This is a simple hand operated EPROM reader.

It would be better to use an EEPROM, but I already had some UV erasable EPROM's.

Step 1: Parts

The only parts you need are:

-An EPROM (in my case a M2732A-4FI)
-LEDs and resistors for them
-A 5V power supply
-Bread Board or any other board

-if you want, you can add switches

Step 2: Schematic

If you think about it, the schematic is really simple. Look at the images for further details.

Step 3: Operating It

Use the A pins for address selection, where the data is stored. When Chip enabled is low, it is active. When Output enabled is low, the chip can output.

The leds show you the written bits.

Step 4: Programming

I need some help at this part.

I need some ideas from where to get 21V, that are needed for programming.

And some ideas on how to select the address that it will write to. I need 12 bits for selection + 8 data bits.
To get 21v you could use a boost converter. Also would it not be a whole lot more easy to attach a microcontroller to read the (e)eprom and hook that up to the serial port so you can dump the entire contents of the chip?
Not really easier. I'm planning to do something like that for programming, but I'm not sure how to transmit the data. Parallel and serial don't have enough pins (unless I improvise) and UART over USB could be hard to make.
<p>if we use a shiftregister on arduino to transmit data </p>
I guess you could try some sort of multiplexing or even simpler use a uC with a high number of I/O pins like the PIC16F59. As you need 12 pins for address, 8 for data, 1 enable,1 rx, 1 tx. That means any uC with 23+ I/O pins could do theoretically
<p>I have a M27C128A thanks for the instructable.... :) </p>
<p>This is pretty cool! I have 4 old eproms laying around from a Bally Midway arcade game (Party animals) and wired this up to test them. The first one worked right away, but the others (And now it) show all the adresses equal to 11111111. All the LEDs light up no matter what adress I enter... Wonder if I'm doing something wrong?</p>
MAKE: magazine writer, Matt Richardson wrote a small blurb about someone who uses a Arduino MEGA2560 as a EPROM (Not EEPROM) reader.. The additional address lines are covered by the many digital lines the MEGA has, compared to the UNO or duemilinov.. I've already devised a simplified Burner idea, but the 21V supply would be a generic transformer/bridge rect... I know, In today's switching technology? I imagine the same device could also be used to write EEPROMs.. (already looking at a 29EE010 (128KB X8, AKA 1 MBit) I pulled from an old Pentium motherboard. Looks like a 1mBit EPROM, but only requires +5V! Go figure?)
This seems so simple, good instructible to help those with unknown UVEPROMs, and I've already been planning on using this idea for testing some of my memory chips and stuff. <br> <br>As for getting 21V cheaply, simply, and easily, you could try a couple of voltage doubler circuits hooked up to an oscillator. 5V from, say, a 555, doubled to 10V, then to 20V. The current would be minimal; check the datasheet for the exact specs on your chip. <br>OR.... <br>Hook some 9v batteries in series: 9v, then 18v, then add two AA batteries for 21v. Might want to test it with a multimeter first to make sure the batteries aren't too high to start with.

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