EPROM Scanning 25-Aug-2010 2:41 PM
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1. EPROM Image Scanner

The basic idea is to scan visual imagery on the programmable field visible through the window on an EPROM. EPROMs have an array of bitwise storage which can be erased with UV light, and programmed electronically.

If you fill the EPROM with a "full burn" and then selectively erase it (basically doing the process backwards) you will fill the EPROM with data that corresponds to the imagery projected on it at erase time.

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1.1. Calibration

Determine the amount of time with the UV Light source required to do a full erase of the EPROM.

  1. Do a full burn
  2. project a bare UV LED onto the EPROM field for N minutes
  3. read in the data to see if it has been erased
  4. repeat until empty
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1.2. Scanning

The basic process for this is simple;

  1. Erase an EPROM (fills it with 0xFF)
  2. Burn out a full-burn of empty (fills it with 0x00)
  3. Project a grayscale image onto the "field" of the EEPROM with a UV LED light source
  4. leave the light source on for the time determined in the above calibration to properly "expose" the EEPROM
  5. dump the data to get the image
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1.3. Complications

It's probably the case that the imagery will not line up physically in-order with the data addressing. Multiple exposures with different images may be necessary to properly map the physical arrangement of the data bits with the memory space.