Microsoft Xbox Repair Manual page 68

which occur during the change. This is the reason for the DIOW-line, to tell the device when the
data lines are stable. Slower measurement devices will (probably) not see these transient results.
If you are unfamiliar with such high-speed devices this can be confusing
Options for those without a logic analyzer
I have had a bunch of questions centered mainly on how to do this without the analyzer or some
other specialized equipment. Generally my answer is: you probably can't. I *seriously* doubt that
any generic input device on a PC can be read at anywhere near the speed required. If someone
really wants to try, my suggestion is to start with the parallel port. I do not know that much about
the parallel port, but you may be able to program it to read the data at a sufficiently fast rate. It
appears to have at least 9 input lines, (though some are inverted) which can be used to read the
pins on the ide cable. You would have to dedicate 6 of these pins to the control signals (CS (1:0)-,
DA (2:0), and DIOW-) and could use the other 3 to gather data from the DD pins. This would, of
course, require multiple runs to gather all of the 16 bits for each word in the password.
The two primary questions I can't answer are the capacitance of the input pins on the parallel port,
and the speed with which they can be polled. If the capacitance is too high you will be ruining the
ide signals, and the Xbox will almost certainly not be able to communicate with the drive at all. If
that is the case it may never get to the stage of trying to transfer the password to the drive (worst
case is it could overheat the IDE controller chipset). If the read speed is too low then you will not
be able to get all of the state changes, and will probably not be able to read anything of use. My
*guess* as to the lowest possible read rate is somewhere around 25MHz. At this rate you will
probably miss some of the DIOW line changes, but should be able to see all of the actual data bus
changes.
If you decide to try this, verify it works on some other drive before using your Xbox drive, as I
have no idea what kinds of problems might come up if it fails.
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