A Simple EPROM Programmer for the Motorola D2 Kit. Add 2K of firmware using a handful of components that fit right on the D2 board. Frank W. Summers. , , , , , , 27C, , 27C, , 27C, 27C, , , EPROM series. EPROM and CMOS. ON-BOARD EPROMS. ·-··~)epar:;t-;; -socket or (31< of EPRO~1s. /\ddressable by DIP swi tch to any 14K or br. bound,lry al)()vc.

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By the A was out of date, its 16k of EPROM space was insufficient for most designs and its power consumption was much higher then contemporary parts. The design was altered to work with the new, smaller process, and it was significant enough to warrant a new copyright.

The programming process is not electrically reversible. The erasing window must be kept covered with an opaque label to prevent accidental erasure by the Erprom found in sunlight or camera flashes. Being as there was 2 versions of the using different parts of the die, its clear Intel 270 using defective die to make theat least early on. Professional tools that can do this task are really expensive. Like EPROM chips, such microcontrollers came in windowed expensive versions that were used for debugging and program development.

Also of note is the different copyrights. Often this label was foil-backed to ensure its opacity to UV. So not only was Vostok able to pass a defective part as a quality part, they were able to do so and make a bit extra revenue.

2708 / 2704 EPROM reader / programmer

Literally this means that the die and masks are scaled down to a new smaller process with no architectural changes. Digital Design and Fabrication.

Views Read Edit View history. Being that its a mask ROM one can actually SEE the connections, so its possible to decap a device, and visually determine the code, albeit with a lot of tedious work.

In other words, to erase ee;rom EPROM, you would first have to X-ray it and then put it in an oven at about degrees Celsius to anneal semiconductor alterations caused by the X-rays. As 278 quartz window is expensive to make, OTP one-time programmable chips were introduced; here, the die is mounted in an opaque package so it cannot be erased after programming — this also eliminates the need to test the erase function, further reducing cost.


EPROMs had a limited but large number of erase cycles; the silicon dioxide around the gates would accumulate damage from each cycle, making the chip unreliable after several thousand cycles. EPROMs are particularly nice as due to the fact that they need a window to allow UV light in for erasure, you can also have a clear shot of the die in most cases. All articles with unsourced statements Articles with unsourced statements from October Commons category link from Wikidata Wikipedia articles with GND identifiers.

Latest CPU Images here. A control gate electrode is deposited and further oxide covers it. It was designed to interface direction to theMCS and i processors. When Intel released the in and A in it provided an easy way to interface the and the to other components.

Intel sought to remedy this with the release of the 87C In other projects Wikimedia Commons. You may also view them in raw directory form here and a few that didnt make it into the gallery here. Its likely these dies had a defect so the affected area was effectively disabled by not using that address line.

Monday September 10th, Tuesday August 5th, admin.

Rewiring address lines likely did not allow for a working EPROM due to where the defect was, thus cutting the word size down. National also using a die.

This certainly was not an uncommon procedure, even Intel regularly sold EPROMs as swhether to use a die with an imperfection, or to simply meet demand. However, these require many weeks lead time to make, since the artwork for an IC mask layer must be altered to store data on the ROMs. Adam Laurie of Aperture Labs developed a Python script to automate some of it, and wrote an article explaining it, which covers some every interesting Mask ROM info. C S — Defective die using only the upper 8k.


Each field-effect transistor consists of a channel in the semiconductor body of the device. This greatly reduced system chip counts and complexity of board design.

At dpi or dpi on one you can see that they are in fact different dies, and both are not dies…. Erasure, however, has to be accomplished by non-electrical methods, since the gate electrode is not accessible electrically. International Trade Commission, ed. Every byte is separated by a space character. EPROM programming is slow compared to other forms of memory.

Shining ultraviolet light on any part of an unpackaged device causes a photocurrent to flow from the floating gate back to the silicon substrate, thereby discharging the gate to its initial, uncharged condition photoelectric effect.

It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages than those normally used in digital circuits.

/ EPROM reader / programmer | Museo dell’Informatica Funzionante

We must simply set the A1 digital port connected to pin 22 of the EPROM to zero, and read only the values between 0 and It was soon found that small-volume production was economical with EPROM parts, particularly when the advantage of rapid upgrades of firmware was considered.

Thats something Intel would be quite envious of. Data is trasmitted to the serial port as an ASCII character, representing the hexadecimal value that has been read. Not to mention some very nice pictures, so check it out.

There are other benefits typically speed increases and power decreases aside from leakage but from a purely economical stand point, the smaller dies result in more profits.