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Best way to deal with multiple tasks that need to read RTC in very short period?

Posted by pugglewuggle on March 15, 2016

Is there an efficient way to communicate with an external RTC and then share that time/value with many tasks that could be requesting that value at any moment without an expensive in/out queue implementation between requesting tasks and the actual RTC task? Surely someone has had to do this before. Thanks!


Best way to deal with multiple tasks that need to read RTC in very short period?

Posted by heinbali01 on March 15, 2016

Hi pugglewuggle,

Is it possible to express the current time as e.g. seconds after 1-1-1970?

Note that there are date-conversion functions in

 FreeRTOS-Plus-FAT\ff_time.c

The cheapest way to share a 32-bit value on a 32-bit MCU would be to declare it as volatile variable:

volatile u32_t ulRTCTime;

( provide an access function if you want to avoid the use of global variables ).

If the architecture not support 32-bit access, you will need a mutex/semaphore to protect the value from getting changed while reading it.

Regards.


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