if (len > 0)
len -= 1
if (len < cmax)
byte[p_str++] := c
len += 1
byte[p_str] := 0
As you can see, this is quite easy. We need to pass a
pointer to the buffer to hold the string, as well as the
maximum number of characters that can be entered. A
repeat loop processes the input as
long as there is room in the buffer. I
do a lot of terminal based work, so I
included the ability to handle the
backspace key to fix a mistake.
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For you fans of the hit TV show,
Mr. Robot, the penultimate episode
from Season 2 was pretty interesting
because there was a major shout-out to my friend, Ryan (1o57)
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Clarke, and the crypto work he did
with the Propeller-powered
DEFCON 22 badge. There are many
strings stored in the badge code that
serve as clues in his crypto puzzle.
14 pin male header, pins on 0.05" centers.
Includes hook-up diagram.
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Knowing that DEFCON attendees
would start by writing a RAM based
program to dump the EEPROM
contents to a terminal, Ryan
encoded the strings using a few
techniques. Well, there was, in fact,
one string that wasn’t encoded that
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CAT# 18BK- 35
$430 per roll
Have a look at Figure 1; this is
the EEPROM map from the strings
demo program. The highlighted
section is a couple encoded strings;
these can be decoded with methods
in the text buffer object. As a tribute
to Ryan and the show, one of the
methods is called .mr_robot() which
runs the ROT- 13 algorithm. If you
answer a question in the demo
program, the strings will be decoded
Trapezoid shaped, it can stand on any of its
four edges. 5.95" x 5.93" x 0.95".
CAT# PF- 2 $495 each 10 for $4.50 each
RE 200B is a passive infrared sensor
designed to pick up heat radiation
in the infrared range. Used in alarm
systems and automatic switches that
respond to human body motion. TO5 metal
case w/ 3 leads.
The crypto methods in the text
buffer object are not secure, and
meant mostly for fun. Still, you can
encode and decode string data with
them that may dissuade less-than-inspired hackers from looking for
information in your EEPROM.
52 November 2016