[Noisebridge-discuss] cheap USB Analyzer, or signal integrity tools?

[Michael Prados]

This sounds really cool, since I am taking apart hard drives all the
time to use the rotary voice coils for my own devious ends, so I'd
definitely like to hear more about this.  I googled the commands you
referenced, and am happy to see that there is some documentation for
the protocol, but am still a little foggy on the higher level layout
of how this would work.

So, you're saying that there is already a good high bandwidth ADC
built into a typical hard drive; is this from the read heads?  So the
idea is that I find a good point to tap into the HD PCB, pipe in my
USB signals, and they get spit out at me in real time over SATA or
whichever other HD interface?

Is it a challenge to keep the hard drive firmware alive once I've
modified the hardware?

Definitely want to try this one out...

-mike

On Mon, Nov 8, 2010 at 1:36 PM, Dr. Jesus <j at hug.gs> wrote:
> On Mon, Nov 8, 2010 at 1:22 PM, Andy Isaacson <adi at hexapodia.org> wrote:
>> On Mon, Nov 08, 2010 at 01:17:03PM -0800, John E wrote:
>>> Are you talking about during assembly or during use?
>>> A couple of diodes in the input stage to protect against being blown up by
>>> static or wrong voltages,
>>
>> I'm not an EE, but it's my impression that building a decent input stage
>> for a 0.5 - 1.0 GHz signal is nontrivial, especially if you want it to
>> be able to withstand 12V shocks (for when your hobbyist user
>> accidentally touches the probe to the power rail while attaching the
>> debugging tool).
>
> If I have to see the signal on some dangerous high speed bus and I
> don't have good gear, I usually wire up a hard drive to the mux chip
> between the logic board and the servo arms.  Seagate drives have a
> serial interface that lets you get into the disk's firmware and use
> the disk controller's internal high speed ADC to break out the ADC
> output to the test pins on the logic board.  Search for "seagate
> diagnostic commands" or "alpine diagnostic commands" for the details.
>
> Most importantly, a disk with a motor problem is usually free anyway,
> so it's not a big deal if you fry it accidentally.  I'm not going to
> claim it's easy or fast to set up, but sometimes it's the only
> realistic option when the other two options are having a staring
> contest with the schematic or getting my hands on a very expensive
> high speed scope.
> _______________________________________________
> Noisebridge-discuss mailing list
> Noisebridge-discuss at lists.noisebridge.net
> https://www.noisebridge.net/mailman/listinfo/noisebridge-discuss
>



-- 
[REMOVE THIS TEXT BEFORE SENDING AN EMAIL!]