[puzzle] Listener, The
kuroneko
Posts: 3,623
The attached program establishes a communication link between two cogs using lock #0. A writer cog starts a reader cog and transfers a 32bit message (preceded by a 1-startbit). I would like to know what the message is without them knowing.
I'm not interested in solutions where someone figures out (or forces) the start time for the writer cog as the message is cnt based and you can read the source. What I'm after is some form of solution which taps the link and e.g. copies the clkfreq/16 Mb/s data stream to a pin. To make this easier I placed both cogs as far apart as possible (N and (N+7)&7). The 6 remaining cogs are available to you.
The primary method looks like this:
I won't bother placing (more) initial limitations on this one. We can sort this out when the relevant bridges are to be crossed (Hi Phil!).
Update: Validation (over here) will use the same communication link but different (unknown to you) message content. And yes, there is at least one solution.
I'm not interested in solutions where someone figures out (or forces) the start time for the writer cog as the message is cnt based and you can read the source. What I'm after is some form of solution which taps the link and e.g. copies the clkfreq/16 Mb/s data stream to a pin. To make this easier I placed both cogs as far apart as possible (N and (N+7)&7). The 6 remaining cogs are available to you.
The primary method looks like this:
PUB null coginit(cogid, @writer, @reader)Your interceptor code will be started before the coginit, e.g. coginit(4, @intercept, parameter). If the reader cog thinks someone was listening it resets the chip (you're not allowed to kill it in order to prevent that). Otherwise it will light up LEDs 22/23 (demoboard).
I won't bother placing (more) initial limitations on this one. We can sort this out when the relevant bridges are to be crossed (Hi Phil!).
Update: Validation (over here) will use the same communication link but different (unknown to you) message content. And yes, there is at least one solution.
