RTOS/TM4C129ENCPDT: I2C_transfer in non-task function

M Syd Ahmed

Tool/software: TI-RTOS

Hello Guys,

I read in user guide that its not possible to call i2c_transfer in non task context. when I looks for the reason, it seems it use semaphore_pend internally. Hence it should be called in task context only. I needs to know if there any chance of calling i2c_transfer in non task context. like blocking all task functions and all. If its possible can someone post pseudo code for that. Our customer demands he needs them in non task context.

over 8 years ago

0 M Syd Ahmed over 8 years ago

Expert 1035 points

i knows Semaphore_pend can be called from swi if timeout is 0. so using that is it possible to call i2c_transfer from non task thread?

0 M Syd Ahmed over 8 years ago in reply to M Syd Ahmed

Expert 1035 points

If i changes semaphore_pend timeout value to 0 in i2c_tiva.c, will i2c run from non task thread.?

0 M Syd Ahmed over 8 years ago in reply to M Syd Ahmed

Expert 1035 points

Finally customer convinced that task should be used. SO am closing this question.

0 Kenia Guinto over 8 years ago in reply to M Syd Ahmed

TI__Expert 7250 points

Glad to see this was resolved.

0 M Syd Ahmed over 8 years ago in reply to Kenia Guinto

Expert 1035 points

If i used semaphore_pend with zero timeout for i2c_transfer, will it transfer whole data?

0 Michel Solecki over 8 years ago in reply to M Syd Ahmed

Mastermind 8415 points

Hi Syed,

I wouldn't recommend playing around with the drivers. It would remove their purpose.

A few things through:

If you want to block tasks while you are transferring data with I2C, you can use Task_disable. This will prevent the task scheduler from switching tasks.

The semaphore is used for synchronization (in blocking or callback mode), so removing it prevents you from knowing whether the transfer completed or not, and whether it was successful. You would probably be able to send messages as long as no error occurs. If any error occurred, you would not be able to start again..

So short answer, the I2C transfer would probably complete, but it is not advisable to do the modifications that you suggested.

Regards,

Michel

0 M Syd Ahmed over 8 years ago in reply to Michel Solecki

Expert 1035 points

Thanks. for now, our customer was happy with using task for i2c sensors. But am not sure will he stick to it. thats why I asked. Anyways will try with task_disable().

Processors

Processors forum

RTOS/TM4C129ENCPDT: I2C_transfer in non-task function