TM4C1294NCPDT program crashing, when UART is initialized twice?

CHAITANYA

Other Parts Discussed in Thread: TM4C1294NCPDT

Controller: TM4C1294NCPDT

IDE: CCS 6.0.1

I am using below code for opening GSM board;

handle = UART_open(UART_GSM, &params);

uart = UART_open(UART_RS232, &uartParams);

and initializing the board parameters by using

handle = UART_open(UART_GSM, &params);

similarly I am doing for UART port:

uart = UART_open(UART_RS232, &uartParams);// uart is the handle parameter I have declared

But when I am doing them consecutively, the program is hanging in between.

My primary requirement is to verify the working of GSM port by sending AT command and displaying the Status on Serial Port.

Thank you,

Chaitanya

chaitanya19924b3@gmail.com

over 9 years ago

0 Amit Ashara over 9 years ago

TI__Guru**** 244400 points

Hello Chaitanya

This seems to be a TI RTOS question

Regards
Amit

0 CHAITANYA over 9 years ago in reply to Amit Ashara

Prodigy 140 points

Is there any other thread or community to post this particular, or is the Tag issue?

0 Amit Ashara over 9 years ago in reply to CHAITANYA

TI__Guru**** 244400 points

Hello Chaitanya

Yes. The TI-RTOS forum

Edit: RTOS got spelt as ROTS

Regards
Amit

0 Soumyajit Das over 9 years ago

Genius 3340 points

Hi Chaitanya,

If you are calling the same function "uart = UART_open(UART_RS232, &uartParams);" twice without calling "UART_close(uart)" in between, then the TI-RTOS may crash. Try calling UART_close() before repeat calling of UART_open() & see the results.

-

Regards

Soumyajit

0 cb1 over 9 years ago in reply to Soumyajit Das

Guru 47900 points

Even if Soumyajit's post doesn't (completely) cure the issue - I believe his method is good & proper...

0 Amit Ashara over 9 years ago in reply to cb1

TI__Guru**** 244400 points

Hello cb1

Doesn't it look kind of strange at least from RTOS that two threads cannot be handled?

Regards
Amit

0 cb1 over 9 years ago in reply to Amit Ashara

Guru 47900 points

Hi Amit,

I'm (far) outside my element w/vendor specific RTOS.

The "matched" openings & closings cannot hurt - and w/in non-RTOS setting proves worthwhile...

0 Amit Ashara over 9 years ago in reply to cb1

TI__Guru**** 244400 points

Hello cb1,

But in your experience don;t you think that a RTOS should be able to support that?

Regards
Amit

0 Robert Adsett72 over 9 years ago in reply to Amit Ashara

Guru 10570 points

Not in my experience Amit,

It's not a question of RTOS use but resource access. Opening a serial port twice is considered a bad thing on most OS. The consequences can vary substantially but a more robust approach will simply refuse to perform a second open w/o an intervening close. If that is the case here then the return from the open will be invalid and using it in subsequent calls may well result in undefined behaviour.

Now an opening of serial port in one thread and it's use in others is less often forbidden. Simultaneous use in multiple threads is a bad idea, usually if you need to access via multiple threads you need some sort of sharing mechanism.

Robert

0 Amit Ashara over 9 years ago in reply to Robert Adsett72

TI__Guru**** 244400 points

Hello Robert

But there should be separate handlers for handling the tasks of each of the ports?

Regards
Amit

0 Robert Adsett72 over 9 years ago in reply to Amit Ashara

Guru 10570 points

Depending on the use it's possible a single handler may use several ports. It also depends on how you define handler.

Having multiple independent threads of execution transmitting out a serial port or reading from a serial port isn't a good idea. Other hardware devices are different. CAN bus peripherals can often have multiple threads of execution for instance.

Robert

0 CHAITANYA over 9 years ago in reply to Amit Ashara

Prodigy 140 points

To be honest, it's a bit very simple thing I missed. I was also closing the UART using, UART_close(&params)(for both the drivers indeed). But some where in the config the file was configured twice and RTOS that lead to the hang of the program. As said by Mr. Amit, it's an absolute RTOS issue.

I found out this issue, by declaring flags at 0 and raising their values and setting to 1.

Well that's indeed a thoughtful approach by Robert. I guess I should configure into a text box and give them respective priorities.

0 cb1_mobile over 9 years ago in reply to CHAITANYA

Guru 117855 points

It's good that you've "Closed the loop" and provided the, "Rest of the story." Thank you.

Arm-based microcontrollers

Arm-based microcontrollers forum

TM4C1294NCPDT program crashing, when UART is initialized twice?