Serial port interfacing the Bus Pirate, Infrared Toy, and Logic Sniffer

While USB is all around us, the humble (virtual) serial port is still everywhere. Today we explore the serial interface on the Infrared Toy, Bus Pirate, and Logic Sniffer. See a demonstration of the binary interfaces and commands normally used only by software utilities.

More: http://dangerousprototypes.com/?p=52413

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Closed Caption:

welcome to today's prototypes I mean
today I'm going to show you how to use
the serial port interface some of our
projects the serial port is a common to
our interface has been around computers
for decades now and even most
microcontrollers have a serial port in
the form of aur is actually the
different voltage levels so it's not
directly compatible with computers even
that with USB is the most popular face
the serial port still with us we're not
playing in serial port cables anymore
though
emulating over USB that's really handy
because devices can be powered by USB
and still appears a simple serial port
to the computer there's a lot of old
applications that work with serial ports
that are still very useful and it's also
a lot easier to write your own software
to work with the serial port even a
simple scripting language like Python or
pearl can use a serial port was just a
few lines of code but if you want to use
USB even something simple like USB HID
going to end up pulling in a lot of
drivers a lot of setup involves gonna be
a lot more difficult
we'll start with the bus pirate because
it's an easy device interface used in ft
2 3 2 USB to serial converter chip that
takes the USB signals and converts them
to 3.3 volt you are that the pic uses to
do all the bus pirate stuff the best
powers interface from a simple serial
terminal freezing teraterm open a
connection to the bus pirate on compton
and we hit enter the command line in the
bus pirate shows this is the high
impedance mode command prompt
it means that nothing is going out of
the bus pirate that means it's safe to
connect your project without worry
there's going to be any damage to it we
can hit I to get some information about
this bus pirate is a version 3d hardware
hit ? and enter to see the menu for the
bus pirate this is all simple stuff this
is just using a simple serial terminal
interface but the most part also has a
binary mode and that's something scripts
can use to send raw by commands to it
and control the different features of
the bus pirate the binary mode needs
characters that we can't type from a
keyboard have to be raw fight values
that are sent to the bus pirate will use
that using a program called Hercules
will open up the most part on content
we're going to type some simple commands
here to like I to get into binary mode
we send 00 20 times it actually 00 typed
out this is the byte value type is a hex
value is sent to the bus pirate and the
best part response it bang I am owed
version 1 so now we're in the binary
mode we can send some other commands
like you're 20 and i squared C mode and
it responds i squared C version one is
all easy stuff all these commands are
completely documented on the wiikey so
if you're writing a script you want to
control the bus hire on these modes it's
just a matter of sending these simple
commands as x values to the bus pirate
over the serial port now let's move on
to the logics never this is a logic
analyzer we could develop with the
gadget factory they can record signals
between two chips and show it as a graph
on the screen
it's a lot easier to debug your project
when you can see why things aren't
working and it is to work blind
this is one of the handiest tools in our
workshop we highly recommend it will
connect to the logics differ on comport
13 it's in normal mode right now and
this speaks was called the some protocol
this is a protocol defines how the field
programmable gate array takes
instructions from the computer and don't
data back to be shown on the display so
first with some protocol will send 05
times to reset it no matter what command
it's stuck in or where it's stuck at the
logic analyzer will be completely reset
after we send 05 times command to
returns the protocol version response
one ALS which is actually some logic
analyzer version one backwards that's a
quirk of the old equipment that was
originally based on one of our
extensions to the sub protocol was a
metadata command returns some extended
data so the software can adjust to
different hardware this wasn't part of
the original some protocol we say
command 04 we get back a descriptor the
first part of the descriptor is filled
01 and that's a text description of the
hardware this attached here it says open
audition for version 1.01 the string is
terminated with the null character which
is 00 the next bit is 0-2 which is the
version and simple tax form also
terminated with the null character and
then from there we have some actual
fight values that so things like the
number of probes the amount of memory so
the client can adapt to the capabilities
of the hardware now connect to the
largest never again this time in update
mode the commands here a little
different
each command is four bytes we send all
four times we get back hardware version
1 firmware 3.0 bootloader version to
point out
other interesting come and we can set
his command one and i'll return the
version of the flash chip on the board
there's actually a whole bunch of
different flash chips out there because
supply changes all the time so we've had
to tweak the software and the firmware
to handle different ships we can get
that version by setting the jtech
command which is a standard command all
flash chips respond to the one command
again is a four by command the first
fight is won the last three by 2017 that
and we get back the jtech ID now
currently we're in text mode way to
switch over to full hex mode and do that
again we said our command 1000 we get
back cf-30 1300 if you look on the
weekly if you look on the internet
you'll find out that that's a win bond
ship with four megabytes of storage
space
another interesting commands the
self-test command that's command seven
this is the same self-test this run
every time the logic analyzer starts up
send it it takes a second the board will
reset our result code zero and that
means there's no errors but let's hold
on the Update button and try it again
this time we get there 20 if you look at
the area code table will show that this
is a problem with the pull-up resistor
on the Update button and it's correct
now let's close that out and move on to
the final device USB infrared toy
this is an infrared receiver training
center computer so you can control your
computer with the remote control you can
also look at the signal logic analyzer
and see what it's doing the IRS way as a
couple different commands it will
actually work from normal serial
terminal so let's check those out first
we sent via will get the hardware and
firmware version in this case is
hardware version 1 firmware version 21
another command is the self-test which
we can get by sending t we type T in
this case it gives us the version again
which means it past the self-test
there's something wrong here we go to
failure code and finally the default
mode of the IR toys and ir man
compatible rc5 decoder the way the
ironman protocol works the pc says ir to
the device the device response ok
in our case we just respond ok anytime
we see the letter R if I had type r into
the terminal we get back okay we know
what we're in rc5 decoder mode most of
the IRA toid commands require all about
values
so now we're going to move over to
Hercules and said some of those this is
an RC 5 remote control the IRS will
decode the codes and show them as six
bike packets in the terminal will hit
play first the button press gave 26 by
packets the remote protocol is money
specific button is 75 and then we've got
four device that will never be anything
with zero we had different buttons we
get different values is play and rewind
and fast-forward and number 1 2 3 4 5 6
and so on the IR 24 MOS the subject
analyzer protocol just like the logics
never logic analyzer does that we can
capture remote control codes and
visualize them on the screen just like
with the logics never will send 05 times
that are reset in the logic analyzer
mode now we can send some simple logic
analyzer commands like to get the
response one analyst which is some logic
analyzer version one just like the
logics never did today we explored three
devices using a serial terminal even
though we live in a world dominated by
USB serial ports are still everywhere
you can use simple techniques like these
to rescue a router or talk to the
bootloader on your digital camera will
be back next week with a new workshop
video thank you for watching