RE: All Lights On/All Units Off and Modifying an MT10

["Mark Hetherington" <mark.egroups@xxxxxxx>]

> > It ought to be trivial even without the source code since
somewhere the
> > button is sending 0001 and I just want to change it to send
> 1101. It might
>
> You obviously are unfamiliar with the X-10 protocol requirements and
> perhaps electronics circuits in general.

Not completely no. I am no expert but never claimed to be. How my mention
of
what binary pattern is sent over the power line is any indication of either
my knowledge of the protocol or electronics I fail to see. The pattern for
All Lights off is 1101, the pattern for All units off is 0001 so whether it
is hardwired or software controlled, this pattern is the required change.

> You are talking about changing
> the preprogrammed X-10 binary command sequence. The buttons are
connected
> directly to the CPU input pins to signal which command has been
selected
> by the user. They don't do the actual sending of X-10 commands.

So the button is hardwired to generate the signal? In which case it is a
resoldering rather than a reprogramming job? Or the button is wired to a
pin
which only issues that command? In my original email I did say I had no
idea
of the internal workings of the MT10 hence my question. You then brought up
the PIC which I further discussed and now I am "obviously unfamiliar
with"
both electronics and the protocol.

> > require some disassembly to locate the exact sequence that
> needs changing
> > but this should be quite trivial. Custom chips would prevent
> this obviously
>
> You probably would not be able to read off the firmware program on
most
> standard microcontrollers, let alone a custom one. Practically all
> programmable chips (OTP, flash, EEPROM) have security protection built
in
> to prevent the disclosure of the control programs inside. There are
ways
> to defeat various protections, depending on how much one is willing to
> spend. There are a small number of chips that can be cracked
relatively
> easily (eg. PIC16F84) but for the majority, the protection is almost
> impossible to defeat by the likes of you and I.

Without access to other resources I would agree. Reading the firmware is
not
a problem I expected to face since I have yet to see one where my contacts
have not been able to get me the firmware off it. I would be surprised if
the MT10 firmware was that well protected anyway since there can hardly be
anything worth the additional expense of protection within it. But people
do
go to great efforts to protect the strangest things so maybe the MT10 is so
highly protected it was impossible. But then again, wasn't that part of my
question.

Mark.


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