JohnDMcMaster / eetime

EPROM Erasure Time: a suite for characterizing EPROMs

eetime

EPROM Erasure Time: a suite for characterizing EPROMs

High level requirements:

• Linux
  • MacOS might work but is untested and I don't have instructions
• TL866 (minipro) family of USB programmer
• Can expose chip to UV while in the EPROM programmer

Refernece setup:

• Ubuntu 20.04
• Original TL866
• Spectronics PE-140T EPROM eraser
• 3D printed adapter
• See: https://twitter.com/johndmcmaster/status/1505276794156376066

More detailed requirements:

• You'll need to run the EPROM programmer while the UV source is on
  • WARNING: UV light is harmful to eyes and skin
  • Take all necessary safety precautions, especially if you modify hardware
  • TL866 is compact and may fit into some erasers
  • Socket extension cable might work
• EPROM isn't sensitive to optical fault injection from your UV source
• If your light source is too strong it will glitch the chip
• Shouldn't be the case for commodity EPROM erasers

See also:

• https://proghq.org/wiki/index.php/EPROM_Sensitivity
• https://proghq.org/media/eetime/

Installation

Install minipro software: https://gitlab.com/DavidGriffith/minipro

For basic data collection there are currently no additional python dependencies. However if you want to graph you'll also need a bunch more stuff (WIP)

numpy
matplotlib

Usage

Use minipro -l to find your device. Example:

$ minipro -l |grep 27C256
...
MX27C256@PLCC32
27C256@DIP28
27C256@PLCC32
27C256@SOIC28
...

I'm using Intel D27C256 which doens't appear in the list, so I'll use the closest match (generic "27C256@DIP28")

Start by seeing if you can talk to minipro using check.py. For example:

$ ./check.py --verbose --device "27C256@DIP28"

If all goes ok it should report whether or not your EPROM is currently blank.

Fully automated collection

Requirements:

• Slow EPROM erase vs programming time
  • Can program the EPROM w/o affecting erase time too much

Example:

$ ./collect.py --device '27C256@DIP28' --passes 12 --write-init --postfix intel_d27c256

Manual collection

This is intended for high intensity sources.

First zero out the EPROM:

$ ./zero.py --device '27C256@DIP28'

Now turn on your UV source and immediately run:

$ ./collect.py --device '27C256@DIP28' --postfix intel_d27c256

Plotting

Either filenames or a single directory can be given. Examples:

$ ./plot.py log/2022-03-19_01_intel_d27c256
$ ./plot.py log/2022-03-19_01_intel_d27c256/*.jl log/2022-03-19_02_intel_d27c256/*.jl

Version history

History:

• v1.0.0
  • It does stuff
• v1.1.0
  • "erase_time" changed from 120% to 100% completion (added "run_time")
  • Added metadata options
  • Write initial EPROM state
  • csv_gen.py, annotate.py
• TBD v1.2.0
  • csv_aggregate.py
  • wps7 wrapper example