Just google linux serial programming. BBB is no different to any other
Linux (or indeed UNIX) box in this respect - here's one for started:
http://tldp.org/HOWTO/Serial-Programming-HOWTO/index.html.
On 29 November 2013 09:51, Andrei Kondratjev <andrej.kondrat...@gmail.com>wrote:
> Thanks again,
>
> Yes, I know I need to write a software, I initially wanted to check the
> method of sending the data over the UART on shell and then write the
> software to do the same thing.
>
> I suppose it's not the best way to include the: system ("echo ..... >
> /dev/ttyO4"), call in the software, as it's the shell that causes the
> problems for me.
>
> Can you maybe suggest the best way how I should address the UART in my
> software, I haven't seen any examples for the UART programming using c/c++
> on beaglebone online.
>
> Thanks
>
>
> On 28 November 2013 18:35, Mike Bremford <m...@bfo.com> wrote:
>
>> It's the shell causing your problems, not the UART. First, it should be
>>
>> "echo -n \\x00 > /dev/ttyO4"
>>
>> Two backslashes (my error, sorry). Second, "man echo" and take a look at
>> the syntax, you can't just do "\xNNNNNNNNN". To repeat, you should really
>> write some software to do this rather than doing it from the shell.
>>
>>
>> On 27 November 2013 09:42, Andrei <andrej.kondrat...@gmail.com> wrote:
>>
>>> Hi Mike,
>>>
>>> I want to send the string of binary data, like 10001111 or 11110011
>>> etc., and I expect to see HIGH and LOW on Oscilloscope.
>>>
>>> When I use command set "echo -n \x01 > /dev/ttyO4" i can see on
>>> oscilloscope
>>> <https://lh5.googleusercontent.com/-SFyPNhrmt1Q/UpW8pMOL1QI/AAAAAAAAAIc/vXwys02_w9k/s1600/TEK00001.PNG>
>>> "echo -n \x1001 >
>>> /dev/ttyO4"<https://lh3.googleusercontent.com/-FM4duvgj-Js/UpW87M2poNI/AAAAAAAAAIk/NiFsI8K2u98/s1600/TEK00002.PNG>
>>>
>>> It is still in ascii, is there a way how to get it to work and send
>>> standard binary string , because my device needs CMOS/TTL logic.
>>>
>>>
>>>
>>> On Tuesday, 26 November 2013 19:53:44 UTC+1, Mike Bremford wrote:
>>>
>>>> I'm really not sure this question at all. UART4 Tx a single wire which
>>>> is high by default. Put a multimeter on the uart4tx pin to confirm this. If
>>>> you send data to it then it goes out in blocks of N bits (N normally being
>>>> 10 - start bit, 8 data bits, stop bit), then returns to the default state
>>>> of high until the next transmission. http://en.wikipedia.org/wiki/
>>>> Asynchronous_start-stop
>>>>
>>>> Do you want to send binary data bit-by-bit, as in: write 1 to it, the
>>>> pin goes high, write 0 and the pin goes low? Then that's not what a UART
>>>> does - sounds like GPIO to me.
>>>>
>>>> Do you want to send the byte 0, as in: start bit, 8 x low bits, stop
>>>> bit? Then "echo -n \x00 > /dev/ttyO4" should do it. But much easier to do
>>>> this in C (or any other language) as the ttyO4 is just a file: open it, set
>>>> it up as a TTY (in C with functions tcsetattr, cfmakeraw etc), then write
>>>> the zero byte to the stream.
>>>>
>>>>
>>>> On 26 November 2013 14:42, Andrei <andrej.k...@gmail.com> wrote:
>>>>
>>>>> Hello Rod,
>>>>>
>>>>> Thanks you for the help on this, was really helpful.
>>>>> But do you know how can I send the binary instead of ascii? (Do I
>>>>> need to put maybe prefix of SB before the value to send binary?)
>>>>>
>>>>> After many unsuccessful attempts of sending binary over UART, I'm
>>>>> looking at possibility to change the UART MODE described in *TI AM335x
>>>>> ARM A8 Microprocessors technical reference manual , *maybe this
>>>>> will allow me to send the binary then.
>>>>>
>>>>>
>>>>> For my project, the transceiver that I wan to connect to UART needs
>>>>> CMOS/TTL logic.
>>>>>
>>>>>
>>>>> On Monday, 25 November 2013 21:05:16 UTC+1, rod calabio wrote:
>>>>>>
>>>>>> Andrei
>>>>>>
>>>>>> ascii for "1" is 00110001
>>>>>> ascii for Line feed is 00001010
>>>>>>
>>>>>> so you will get
>>>>>> st=0
>>>>>> d0 = 1
>>>>>> d1 = 0
>>>>>> d2 = 0
>>>>>> d3 = 0
>>>>>> d4 = 1
>>>>>> d5 =1
>>>>>> d6 = 0
>>>>>> d7 =0
>>>>>> sp = 1
>>>>>> st = 0
>>>>>> d0 = 0
>>>>>> d1 = 1
>>>>>> d2 = 0
>>>>>> d3 = 1
>>>>>> d4 - d7 =0
>>>>>> sp = 1
>>>>>> idle = 1
>>>>>>
>>>>>> --
>>>>> For more options, visit http://beagleboard.org/discuss
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>>>>
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