Im currently working on trying to reverse engineer a USB puzzle board I was given. (its a ATMega168 based device with a standard FTDI USB to UART chip) and all the information you are given is you may need programming and electronic investigation tools to work it out.
Anyway I found the following signal on the SCA pin from the MCU but cant identify what it is. its on the i2c bus, clock line goes high and stays high.
Anyone know what it is? If it helps I can send a dump of the MCU which will runin AVS Studio 4 simulate and let you interact with the uart whrre the main puzzles are.
also is there any way I can work out what pins are used for what? im sure I need to interface with them in some way to activate things. the board has the following pins exposed for connections on the back via pads on the pcb. on the front is a standard SPI bus connector which all I dont know how to check if their is anything on there I can interface with using a bus pirate. (new to MCUs and the bus pirate but did managed to use it to pull a copy of the code from it)
- VCC
- GND
- PCINT19/OC2B/INT1
- PCINT0/CLKO/ICP1
- PCINT1/OC1A
- INT0/PCINT18
- VCC
- GND
- ADC1/PCINT9
- ADC0/PCINT8
- ADC4/SDA/PCINT12
- ADC5/SCL/PCINT13
- VCC
- GND
- SCK/PCINT5
- PCINT4/MISO
- PCINT3/OC2A/MOSI
- PCINT2/SS/OC1B