Accessing the serial port with RTEMS
hwulf at et-inf.fho-emden.de
hwulf at et-inf.fho-emden.de
Fri Apr 20 15:19:50 UTC 2007
I think there's another problem because I'm running the RTEMS program
in the TSIM simulator which simulates a leon3 processor. Anyway, the
program can't find the serial devices "COM1" and "\\\\.\\CNCA0"
(which is a virtual com port I created with the open source program
com0com).
Are you comfortable with the TSIM simulator?
How could I access its serial ports?
I wanted to connect the TSIM simulator with a hyperterm by using the
two virtual serial ports "\\\\.\\CNCA0" and "\\\\.\\CNCB0" created
with com0com. So it should be possible to write something in the serial
port of TSIM and see the output in the hyperterm. But I don't know
how the device files are named in TSIM.
Thank you very much and kind regards,
Hank
Quoting Joel Sherrill <joel.sherrill at oarcorp.com>:
> hwulf at et-inf.fho-emden.de wrote:
>> When I print out an error message with perror(),
>> it says "Too many open files in system"
>>
>> Why is this?
>>
>>
> Because there are too many open files in the system. :)
>
> The default configuration is for 3 file descriptors -- stdin,
> stdout, and stderr. You need to change the value of this
> configuration parameter.
>
> #define CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS 3
>
> Discussed in the documentation here:
>
> http://www.rtems.org/onlinedocs/releases/rtemsdocs-4.7.1/share/rtems/html/c_user/c_user00389.html
>
> --joel
>> Thank you very much and kind regards,
>> Hank
>>
>> Quoting hwulf at et-inf.fho-emden.de:
>>
>>
>>> Hi,
>>>
>>> I wanted to access the serial port with RTEMS.
>>> As RTEMS is compliant to the POSIX standard,
>>> I thought of using the POSIX functions for it.
>>>
>>> But I can't open the serial port with the open()
>>> function. Does anyone have an advice of what's
>>> wrong with the code?
>>>
>>> Or is there another way to access the serial port?
>>>
>>> Thank you very much in advance and kind regards,
>>> Hank
>>>
>>>
>>>
>>> /******************************************************************************
>>> *
>>> * INCLUDES
>>> *
>>> *
>>> ****************************************************************************/
>>> #include <rtems.h>
>>> #include <stdio.h>
>>> #include <string.h>
>>> #include <unistd.h>
>>> #include <fcntl.h>
>>> #include <errno.h>
>>> #include <termios.h>
>>>
>>> /******************************************************************************
>>> *
>>> * FUNCTION PROTOTYPES
>>> *
>>> *
>>> ****************************************************************************/
>>>
>>> rtems_task Init(rtems_task_argument argument);
>>>
>>> /******************************************************************************
>>> *
>>> * GLOBAL VARIABLES
>>> *
>>> *
>>> ****************************************************************************/
>>>
>>> /*
>>> * Keep the names and IDs in global variables so another task can
>>> use them.
>>> */
>>>
>>> /******************************************************************************
>>> *
>>> * CONFIGURATION INFORMATION
>>> *
>>> *
>>> ****************************************************************************/
>>> #include <bsp.h> /* for device driver prototypes */
>>>
>>> #define CONFIGURE_INIT
>>> #define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
>>> #define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
>>>
>>> #define CONFIGURE_MAXIMUM_TASKS 3
>>> #define CONFIGURE_MAXIMUM_MESSAGE_QUEUES 2
>>> #define CONFIGURE_MAXIMUM_SEMAPHORES 5
>>>
>>> #define CONFIGURE_RTEMS_INIT_TASKS_TABLE
>>>
>>> #define CONFIGURE_EXTRA_TASK_STACKS (2 * RTEMS_MINIMUM_STACK_SIZE)
>>> #define CONFIGURE_MICROSECONDS_PER_TICK 10000
>>> //#define CONFIGURE_TICKS_PER_TIMESLICE 5
>>> //#define CONFIGURE_MEMORY_OVERHEAD 1000
>>> //#define CONFIGURE_EXECUTIVE_RAM_WORK_AREA 1000
>>> #define CONFIGURE_INIT_TASK_INITIAL_MODES (RTEMS_PREEMPT | \
>>> RTEMS_NO_TIMESLICE | \
>>> RTEMS_NO_ASR | \
>>> RTEMS_INTERRUPT_LEVEL(0))
>>> #define MAX_ITERATIONS 20
>>>
>>> #define _DEBUG_
>>>
>>> #include <confdefs.h>
>>>
>>> /******************************************************************************
>>> *
>>> * MACROS
>>> *
>>> *
>>> ****************************************************************************/
>>> /*
>>> * Macro to print an task name that is composed of ASCII characters.
>>> *
>>> */
>>>
>>> #define put_name( _name, _crlf ) \
>>> do { \
>>> rtems_unsigned32 c0, c1, c2, c3; \
>>> \
>>> c0 = ((_name) >> 24) & 0xff; \
>>> c1 = ((_name) >> 16) & 0xff; \
>>> c2 = ((_name) >> 8) & 0xff; \
>>> c3 = (_name) & 0xff; \
>>> putchar( (char)c0 ); \
>>> if ( c1 ) putchar( (char)c1 ); \
>>> if ( c2 ) putchar( (char)c2 ); \
>>> if ( c3 ) putchar( (char)c3 ); \
>>> if ( (_crlf) ) \
>>> putchar( '\n' ); \
>>> } while (0)
>>>
>>> /*
>>> * This allows us to view the "Test_task" instantiations as a set
>>> * of numbered tasks by eliminating the number of application
>>> * tasks created.
>>> *
>>> * In reality, this is too complex for the purposes of this
>>> * example. It would have been easier to pass a task argument. :)
>>> * But it shows how rtems_id's can sometimes be used.
>>> */
>>>
>>> #define task_number( tid ) \
>>> ( rtems_get_index( tid ) - \
>>> rtems_configuration_get_rtems_api_configuration()->number_of_initialization_tasks
>>> )
>>>
>>>
>>> #include <stdio.h>
>>>
>>> /*
>>> * Keep the names and IDs in global variables so another task can
>>> use them.
>>> */
>>>
>>> /******************************************************************************
>>> * Shared data. Use them with semaphores only!
>>> * Task1_postbox is protected by semaphore with ID 0,
>>> * Task2_postbox is protected by semaphore with ID 1.
>>> *
>>> ****************************************************************************/
>>>
>>>
>>>
>>> /******************************************************************************
>>> *
>>> * INIT
>>> *
>>> *
>>> ****************************************************************************/
>>> rtems_task Init(rtems_task_argument argument)
>>> {
>>> rtems_status_code status;
>>> int fd = 0;
>>> struct termios options;
>>>
>>> /* open the serial port */
>>> fd = open("\\\\.\\CNCA0", O_RDWR | O_NOCTTY | O_NONBLOCK);
>>> if(fd == -1)
>>> printf("Could not open serial port \\.\CNCA0.\n");
>>> else
>>> fcntl(fd, F_SETFL, 0);
>>>
>>> /* get the current options */
>>> tcgetattr(fd, &options);
>>>
>>> /* setting the baud rate */
>>> cfsetispeed(&options, B19200);
>>> cfsetospeed(&options, B19200);
>>>
>>> /* set raw input, 1 second timeout */
>>> options.c_cflag |= (CLOCAL | CREAD);
>>>
>>> /* 8N1, no parity */
>>> options.c_cflag &= ~PARENB;
>>> options.c_cflag &= ~CSTOPB;
>>> options.c_cflag &= ~CSIZE;
>>> options.c_cflag |= CS8;
>>>
>>> options.c_cflag &= ~(CRTSCTS); /* no hardware flow control */
>>> options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
>>> options.c_oflag &= ~(OPOST);
>>> options.c_cc[VMIN] = 0;
>>> options.c_cc[VTIME] = 10;
>>>
>>> /* set the options */
>>> tcsetattr(fd, TCSANOW, &options);
>>>
>>> if(write(fd, "ATZ\r", 4) < 0)
>>> printf("write() of 4 bytes failed!\n");
>>>
>>> exit(0);
>>> }
>>>
>>> _______________________________________________
>>> rtems-users mailing list
>>> rtems-users at rtems.com
>>> http://rtems.rtems.org/mailman/listinfo/rtems-users
>>>
>>>
>>
>>
>>
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>> rtems-users at rtems.com
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>>
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