Hello Micka,
Thanks for your prompt response. I was using 115200. Now I have tried with
38400 and 9600 as well but still the problem persists.
Can you do me a favor? Can you please send the termios structure
configurations with which query-response type application works at your
end? Here is the configurations I am using:
struct termios my_termios, new_termios;
int fd0 = open("/dev/ttyO4", O_RDWR | O_NDELAY | O_NOCTTY);
tcgetattr(fd0, &my_termios);
my_termios.c_iflag &= ~(IGNBRK | BRKINT | ICRNL | INLCR | PARMRK |
INPCK | ISTRIP | IXON);
my_termios.c_oflag &= ~(OCRNL | ONLCR | ONLRET | ONOCR | OFILL |
OLCUC | OPOST);
my_termios.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN | ISIG |
ECHOK | ECHOCTL | ECHOPRT);
my_termios.c_cflag &= ~(CSIZE | PARENB);
my_termios.c_cflag &= ~CRTSCTS;
my_termios.c_cflag |= CS8 | CLOCAL | CREAD;
my_termios.c_cflag &= ~CBAUD;
my_termios.c_cflag |= B9600;
my_termios.c_cc[VMIN] = 0;
my_termios.c_cc[VTIME] = 5;
rv = tcsetattr(fd0, TCSANOW, &my_termios);
tcgetattr(fd0, &new_termios);
Thanks,
Ashish
On Monday, January 27, 2014 7:23:01 PM UTC+5:30, Mickae1 wrote:
>
> What is the baudRate ? Can you spy the communication with an other device
> ? ( serial adapter rs485/rs232 )
>
> In my case, baudrate 38400 work pretty well, without noise.
>
> and please don't UNDERLINE !
>
> Micka,
>
>
> On Mon, Jan 27, 2014 at 10:54 AM, <[email protected] <javascript:>>wrote:
>
>> Hi All,
>>
>> I have a interesting issue:
>>
>> What I have did is:
>>
>> - Downloaded Angstrom linux
>> - Applied RS485 patch
>> - Compiled kernel image and push it to BBB.
>>
>> Now I have developed two applications:
>>
>> 1. send.c : This application periodically sends the data on UART
>> 2. recv.c: This application waits to read the data from UART.
>>
>> Both above application works pretty well without any issue. Even I do not
>> have to manually drive the GPIO. (Driver patch handles GPIO value
>> perfectly.).
>>
>> *Problem:*
>>
>> *Now, I have developed an application which is combination of both send
>> and recv. I mean , after sending one byte on UART from BBB to other host
>> machine, I just wait for input bytes to receive(added receive timepout at
>> 10 sec). Now in this cae, even if I do not send any character from host
>> machine, BBB detects one/two arbitary bytes. This seems that driver changes
>> GPIO position (from send mode to recv mode) before transmitte buffer gets
>> empty. *
>>
>> Did any one has face this problem? Can you guys please share your
>> thoughts on this?
>>
>> Thank,
>> Ashish
>>
>> On Tuesday, December 3, 2013 11:23:48 PM UTC+5:30, [email protected]:
>>>
>>> Zach,
>>>
>>> That is great info!
>>>
>>> Thanks a bunch,
>>>
>>> Haik
>>>
>>> On Tuesday, December 3, 2013 11:42:10 AM UTC-5, Zachary Thorson wrote:
>>>
>>>> I am using a custom built cape for my application, so I have not tested
>>>> it. Though according to the schematics it looks like the chip does not
>>>> support those rates.
>>>>
>>>> According to the schematic at:
>>>> http://beagleboardtoys.info/index.php?title=BeagleBone_RS485
>>>>
>>>> It looks like the RS485 cape uses a TI transceiver part no: SN75HVD12D
>>>> http://www.ti.com/lit/ds/symlink/sn75hvd12.pdf
>>>>
>>>>
>>>> <https://lh6.googleusercontent.com/-iazVOLORISQ/Up4HgMpjUQI/AAAAAAAAA54/FZqOvYcHf28/s1600/12-3-2013+10-31-36+AM.png>
>>>>
>>>> Should be able to go up to 1Mbps, but not much higher.
>>>>
>>>> Checking the ARM Datasheet (AM335x ARM Cortex -A8 MPU Technical
>>>> Reference Manual):
>>>>
>>>> 19.1.1 UART Mode Features
>>>> The general features of the UART/IrDA module when operating in UART
>>>> mode are:
>>>>
>>>> - 16C750 compatibility
>>>> - Baud rate from 300 bps up to 3.6864 Mbps
>>>> - Auto-baud between 1200 bps and 115.2 Kbps
>>>>
>>>>
>>>> Since on the ARM side, you have slightly higher max data rates, so if
>>>> you had a faster chip you could approach the rate you need given the right
>>>> design. If you need faster than what is natively on the ARM, you could
>>>> look into a custom solution with the PRU, but I don't have any experience
>>>> with that.
>>>>
>>>>
>>>> Zach
>>>>
>>>> On Tuesday, December 3, 2013 6:17:45 AM UTC-6, [email protected]:
>>>>>
>>>>> Hi Mika,
>>>>>
>>>>> I need to go two orders of magnitude higher (3.8 Meg, for a short
>>>>> distance of six feet, half duplex). Is there a chance with BBB?
>>>>>
>>>>> Thanks,
>>>>> Haik
>>>>>
>>>>> On Tuesday, December 3, 2013 3:40:39 AM UTC-5, Mickae1 wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> Well, I'm working with the BaudRate 38400 and I don't have any
>>>>>> problem. I didn't try further.
>>>>>>
>>>>>> micka,
>>>>>>
>>>>>>
>>>>>> On Tue, Dec 3, 2013 at 3:13 AM, <[email protected]> wrote:
>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> Interesting Work! What is the max baud rate you can get from this
>>>>>>> rs485 cape on BBB?
>>>>>>>
>>>>>>> Haik
>>>>>>>
>>>>>>>
>>>>>>> On Friday, June 21, 2013 5:54:29 AM UTC-4, Mickae1 wrote:
>>>>>>>>
>>>>>>>> Hi all,
>>>>>>>>
>>>>>>>> Yes I did it ^^, I successfully made my BBB ( Kernel 3.8.x ) work
>>>>>>>> with the *RS485 CAP ( I was able to talk with my PC with a
>>>>>>>> USB<>RS485 adaptater ) *
>>>>>>>>
>>>>>>>> To do it, I modified the Kernel (omap serial driver) and I tested
>>>>>>>> it on a Ubuntu Distribution ( Why ? Because I don't know how to modify
>>>>>>>> the
>>>>>>>> source code of the kernel with an angstrom distribution. And Robert
>>>>>>>> Nelson
>>>>>>>> explain very well how to do it with a Ubuntu distribution).
>>>>>>>>
>>>>>>>> It's true, that the eMMC use the GPIO1_0 & GPIO1_4 of the BBB and
>>>>>>>> the RS485 cap need them, but it's also *easy *to disable the
>>>>>>>> virtual cap eMMC! Just a simple echo -4 > $SLOTS do the trick.
>>>>>>>> And I also had to create my own rs485 virtual cap to enable the
>>>>>>>> GPIO1_0 & GPIO1_4 & UART1_TX & UART1_RX
>>>>>>>>
>>>>>>>> But now, for my project I need to cross compile, and it looks like
>>>>>>>> that there is no toolchain on the ubuntu distribution (working with
>>>>>>>> the
>>>>>>>> Robert Nelson Ubuntu distribution).
>>>>>>>>
>>>>>>>> So I'm going back to the Angstrom distribution, but my problem is
>>>>>>>> that I don't know where to put my patch ? Will it work ? I don't know
>>>>>>>> how
>>>>>>>> to create a patch, I just did this command : " sudo git diff >
>>>>>>>> ../rs485.patch" ( Robert Nelson => on your KERNEL folder )
>>>>>>>>
>>>>>>>> I read here => http://downloads.angstrom-distribution.org/demo/
>>>>>>>> beaglebone/
>>>>>>>>
>>>>>>>> That i can create my own image, with this :
>>>>>>>>
>>>>>>>> git clone git://github.com/Angstrom-distribution/setup-scripts.git
>>>>>>>>
>>>>>>>> cd setup-scripts
>>>>>>>>
>>>>>>>> ./oebb.sh config beaglebone
>>>>>>>>
>>>>>>>> MACHINE=beaglebone ./oebb.sh bitbake systemd-image
>>>>>>>>
>>>>>>>>
>>>>>>>> My question is where I can put my patch ? Or where I can modify the
>>>>>>>> Kernel ?
>>>>>>>>
>>>>>>>>
>>>>>>>> Thx you every one, It's because of your help, That I was able to
>>>>>>>> make this Work !
>>>>>>>>
>>>>>>>>
>>>>>>>> I will soon explain my work on this project in my blog.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Michael Musset,
>>>>>>>>
>>>>>>> --
>>>>>>> For more options, visit http://beagleboard.org/discuss
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>>>>>>>
>>>>>>
>>>>>> --
>> For more options, visit http://beagleboard.org/discuss
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