Sniff EEPROM

Hey can i simply connect my micro to a already running systems eeprom and have it just read the data on the I2C line?

I want to hack something and so i need to read the eeprom... the thing is i dont want to harm the device in anyway possible. So i want to see whats being read from the system, is it safe to assume i can simply connect the data and sck lines and read it?

or should i use a buffer or something in between ?

Hi Jason! Theoretically I think it would work as the I2C pins are tristate and require the pullups that are in circuit... However if the designer HASN'T included bus collision detection (I know I don't, as I have one master and a few slaves) you could damage the master in the circuit.

It's easy, just connect to the target through some high value resistors, after connecting the 2 device grounds.

The high value resistors will stop any problem from the sniffer loading the target. Depending on wire length and speed of the data there will be an upper limit on the resistor values but I think you could start with 10k resistors without too many problems.

Ok cool sounds like fun, i might be releasing a new product soon, would i get in trouble for making a clone of a device? If so heh no new product ... If so expect to save over $100

Ian Rogers said:

Hi Jason! Theoretically I think it would work as the I2C pins are tristate and require the pullups that are in circuit... However if the designer HASN'T included bus collision detection (I know I don't, as I have one master and a few slaves) you could damage the master in the circuit.

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You can't possibly damage anything, because I2C is an open-collector system - which makes it impossible.

Also, as he's only 'sniffing' (reading) there's no writes involved anyway.

I2C 'sniffers' are fairly common, the main problem of course is that you're getting all data on the bus, so you have to identify which data is coming from which IC.

As Mr RB sugested, adding a couple of series resistors would prevent any possiblity of upsetting things, but if the sniffer is designed properly they aren't needed - a high impedance input doesn't load the bus in anyway.

There is only 1 MCU and one I2C device. should be simpleenough i hope heh. I just have to get a T3 tip for my screw driver. My set goes down to T5 only

Got to open it first heh

Ok is this ethical ...?

... Lets say i make a PICKIT 2 clone using a AVR instead of a PIC18F2550 would it qualify as unethical?

Like basically if i make a device that uses other peoples software via PC. Im not sure if its possible yet but contemplating creating a clone.

PICKIT 2 is just a example... its not the actual device im talking about

It's illegal because the manufacturer most likely patented their software. Even if they didn't, it's copywrite.

mynameisdan said:

It's illegal because the manufacturer most likely patented their software. Even if they didn't, it's copywrite.

Click to expand...

Post it here please:

https://www.electro-tech-online.com/threads/clones.120352/