[chirp_devel] any Chirp developers in NJ, NY, or PA?

4 Jan 2018

Hi Rob, welcome to the world of reverse engineering techniques in
python.

/Grab a cup of coffe/tea/soda as this is a medium/log sized email. /

A Chirp's dev as a elmer in the "next block" is a pure gold mine,
but as this is a rare case I suggest you to dig on this:

  * Get comfortable with python language, its learning curve is
    one of the most pleasant and fast I have found

I learned python building a driver for the Feidaxin FD-268A
(https://chirp.danplanet.com/issues/2169
<https://chirp.danplanet.com/issues/2169>) and two years after
that (now) I have supported a few other models of Feidaxin, the
first wave of B-TECHs and its long clone family (remotely with the
great help of Jim Unroe), The Kenwood Family 60 and 60G and
recently the Baofeng BF-T1 (with help of the users
https://chirp.danplanet.com/issues/4933
<https://chirp.danplanet.com/issues/4933>)

When you get the swing and you have the help of the users you can
do drivers without touching the radio it self! for example the
B-TECHs and the recent Baofeng BF-T1.

The best learning material is the Chirp code base, you will have
buch of examples to play with.

Review the Chirp's wiki page about developing a new model, there
you will learn how to setup a correct environment to start, an a
few trick more.

Google is your friend, ask anything about python & you will get a
few dozens of hits for every question you make.

  * Get some background on some important things you will need, as
    usual google is your friend.

You need to understand some concepts like (to start):

      * Numeric representations y different bases (hexadecimal and
        bit tinkering)
      * Boolean and arithmetic operations (and, or, xor and it's
        combinations)
      * String and numeric representation in python, including
        conversions between formats.
      * Data encoding: Little/Big endian, BCD, etc.
      * Serial communications.
      * Regular expression matching (for the serial capture log
        cleaning)

My roadmap for someone that start to develop is like this (very
similar to other suggestions)

  * Get a already supported & cheap radio, and do a reverse
    engineering by yourself, use a simple radio if possible (not a
    driver with multiple variants) use the already made driver as
    a cheat sheet, but not too much... don't be surprised to find
    bugs or to add new features not supported by the original
    developer)
  * Let me suggest you an inexpensive and easy radio for this:
    Baofeng BF-T1.
  * Then go to a more complicated model to understand the concept
    of supporting multiple radios on a single driver and a few
    more new techniques. ( a few candidates for this stage:
    Baofeng UV-5R, B-TECH)
  * Very important point: look and learn from your radio family,
    the one you pretend to support (kenwood, yaesu, baofeng, etc.)
    All families has a very similar logic and structure.
  * Now got your hands dirty with the dev stage.

The main dev steps are this (at least for me):

1 - Get a serial capture log for the download and upload processes.

Go to
http://chirp.danplanet.com/attachments/2257/how%20to%20portmon.doc
<http://chirp.danplanet.com/attachments/2257/how%20to%20portmon.doc>
and learn how to capture a log, if you don't has a Windows at 32
bits then use other port serial monitors, free alternatives are
usbpcap and wireshark (there are some freeware tools out there
too, google "serial monitor eltima") all comments on the settings
for the capture about logging time and hex + ascii are valid.

In this point a good editor text editor (geany, notepad++, gedit)
with regular expression support will help you to "clean" and get a
log with just the needed data and no more comments and notices...

2 - Analyze the serial stream logs, you need to figure out the
serial details (baudrate, transfer bits, parity & stop bits) and more

Usually the radios has a magic string and then a ident string, not
all works the same, Yaesu has a key combinations to send/capture
data, etc...

The magic string is the string you send to the radio to put it on
clone mode, usually they answer back with a fer chars.
The ident string is a special request to retrieve radio
identifications as full model and some other useful info (band
data, options installed, firmware version, etc.)

3 - Figure out the clone logic.

Usually you has to send a crafted string of a few bytes with a
command, an address to start to read and the amount of data you
want; you will identify it easily as they repeat itself
incrementing the address part of the string.

Following this request the radio answer with a block of data that
may/may not contain a kind of echo of the request and then the
data payload you want to read.

You can search the drivers already in chirp to identify similar
drivers you can reuse for that and to understand the clone logic.

4 - Build a skeleton of the driver for only download and radio image.

In this step you can reuse a similar driver, concentrate into
download an image.

5 - Get upload support.

Do step 3 but for the upload process, build the upload procedures,
test and validate.

At this point you are wondering if writing an incorrect data
stream will damage the radio... for this there are 50% chance of
brick your radio for some models, but that's 100% recoverable:

Before playing with upload get a copy of your radio mem (codeplug)
with your OEM software; if you brick your radio, simply power
cycle it and upload the codeplug with the OEM software. Done, you
are set again to play.

Note that we are not changing a bit of the radio memory yet, so
download and upload must not affect the functioning of the radio.

6 - Reverse-engineer the memory data.

If you are working in Linux (which I encourage to do so) you have
a few tools at disposal, "hd" command utility is your best friend
and the hexdiff script is a joy
(https://chirp.danplanet.com/projects/chirp/wiki/DevelopersAdd_a_Radio
<https://chirp.danplanet.com/projects/chirp/wiki/DevelopersAdd_a_Radio>)

Follow this steps: (use a paper and pencil or a digital notepad to
write down your findings if you are not familiar yet with MEM-FORMAT)

6.1 OEM soft: program just one channel with a simplex freq on it,
save to radio
6.2 Chirp: read image, save as base.img
6.3 OEM soft: same channel, change the RX freq, save to radio
6.4 Chirp: read image as new
6.5 Use hexdiff to compare images... now you have found where it
store channel #1.

Using that algorithm determine channel structure and data:

  * TX and Rx are stored as is or base +/- offset
  * What about Rx tones, Digital tone, inverted tone?
  * Same for Tx tone...
  * Repeat with every other channel property (scan/skip, power, name)

And go for a mid and then the final (last channel) to determine
boundaries of the channel data... then learn

Now see some other drivers to learn/improve how to represent your
findings on MEM_FORMAT language...

Don't forget to COMMENT EVERYTHING that is not obvious in the code
reading,

7 - Build the memory parse functions

Use other drivers to represent your MEM_FORMAT in channel data for
the UI. At this point you will get chirp represent your data in a
visual way, polish and validate it, test the limits of data and
validate for that.

8 - Re-do point 6 but for Settings....

Learn how to represent them from other drivers code.

9 - Now try to validate the driver against the Chirp's test bed,
with run_test and/or tox...

You will find more and more errors in your code, validations are
need here and there, prep up your code...

Test it extensively against your hardware...

10 - Submit a patch.

See the wiki to know how to deal with mercurial.

Every radio is different, you will even find bugs in serial
communication (first ident try result in a bad checksum) etc, the
hell is in the details and you need to triage them to find the
solution.

If you are unlucky you will need to make yourself a new way, like
a OM recently did in finding the brick of the encryption schema in
the Wouxun KG-UC8D Plus, and opening a door for me too develop a
driver for the KG-UV8E and T and possible for the UV9D Plus also.
(https://chirp.danplanet.com/issues/3943#change-15199
<https://chirp.danplanet.com/issues/3943#change-15199>)

This is my 10c contribution, don't give up. Ask me for help any
time you want (direct mail or via the list), I'm not in the "next
block" or "around the corner" but I will help you as much as is
possible to me. I'm not 100% of the time online, as Internet is a
scarce and expensive resource here in Cuba, so you may wait for
and answer from me, I try to connect at least twice a day to check
when an active development is on going.

Finally take a time to see this video to learn a few tips to deal
with an Open Source Community with his soft and rough edges:
https://www.youtube.com/watch?v=7XTHdcmjenI
<https://www.youtube.com/watch?v=7XTHdcmjenI>

73 Pavel CO7WT...

El 04/01/18 a las 12:39, Rob Owens via chirp_devel escribió:

Rob Owens

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Rhett Robinson

Rob Owens

Rob Owens

Rhett Robinson

Dan Smith

Dan Smith

Pavel Milanes

Rhett Robinson

Pavel Milanes

Rob Owens

Pavel Milanes

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