Serial hacking with an ATtiny2313

board

[Sprite_tm] automated a portion of serial hacking by sniffing out the baud rate using an ATtiny2313 and FT232 breakout board. The firmware assumes 8 data bits, no parity, and 1 stop bit (8N1). This is pretty much defacto among serial ports so it should work well, though some devices do use different settings. The auto detection routine can sniff rates as low as 110 baud and supports non standard rates. Released under GPLv3, the software is also supplied in hex format.  [Sprite_tm] has provided great project in past such as Working with VFDsControllable bristlebot, and AVR boost converter. Additional information regarding serial hacking after the break.

A great deal of electronics have an Achilles’ heel, known as a serial port. These embedded ports are often used during development to debug functions, load and upgrade firmware etc. At the very least circuit traces are generally brought out for automated testing purposes. Looking up chip pin outs and tracing circuits is one small step in serial hacking. After the traces are known the voltage level is then determined(CMOS,TTL,RS232,etc). Then a few tests are run on the port. These tests generally give indications regarding the potential of the port(does it have a driver, does it have a protocol, what is the baud, etc). If information regarding the baud and other criteria can not be found in the data sheet, [Sprite_tm]’s method would certainly save a great deal of tedious time. Some controllers, like the 68HCxx may have a boot ROM which eliminates most of the guess work in setting up the serial port. We use the Null-modem emulator project (com0com) almost daily to help sort various serial problems. This is highly recommended,  for anyone spending a considerable amount of time with serial devices.

19 thoughts on “Serial hacking with an ATtiny2313

  1. not gonna comment will just read followups from those who will trumpet how they did it better

    although i have to wonder if my annoyance deterrent is working the last few days – everyone’s been rather polite all things considered

    well, at least until the next arduino hack

  2. Anybody else know of any cool serial port tools like com0com and the autobaud device ? would be nice to build a list of opensource software and diy tools/hardware that one can build for hardware hacking en serial port debugging

  3. “although i have to wonder if my annoyance deterrent is working the last few days – everyone’s been rather polite all things considered”

    It has indeed been very polite the last couple of days, but certainly not because of you.
    Perhaps its simply because the articles haven’t been just filler crap.

    Someone actually is either paying attention to getting worthwhile projects to spotlight, or just randomly lucked into solid content. Either way time will tell.
    In any case I like it.

  4. Just realized, most of the last several projects have had arduinos, with no negative comments.

    just a guess – Perhaps thats because the arduino was really the right tool for the job, needed and utilized, as opposed to an idiot duct taping on an arduino >instead< of actually hacking?

    Perhaps people on a hacking site rate things by its hacking value, not by its presence of an arduino or not?

    contains arduino != automatically being a good hack
    being a good hack = being a good hack

  5. @stunmonkey: I agree that not everything that shows up here is particularly impressive, and Arduino nut-hugging is pretty rampant.

    You generally seem to assume that every project that is selected on HaD needs to be a “hack” of some variety. Surely that robot project yesterday is worth bringing to the attention of the readers, even though it’s not a hack per se. Maybe you should petition them to change the site to Project a Day or something…

  6. @second “not gonna comment will just read followups” Hahaha, oh the irony ;)

    This hack is damn cool, with this + a standard pc + putty you will be debugging undocumented serial ports in no time :)

  7. Cypress makes a PSoC (CY8C24x94 for example) which has a USBUART user module that implements this functionality with virtually no effort.

  8. Far be it for me to ask something on-topic, but where is the link to the code on the website? I read and re-read all 4 pages and couldn’t find it anywhere.

    For the rest, I’d worry more about actually building something rather than complaining about the hack-a-day content. I don’t mean to insult, but really, how much time did you spend on your project and how much time did you spend reading hack-a-day? It’s up to you to help create the content you see on this site, imho.

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