MQX Software SolutionsのトピックRe: periodic timer. Restriction on notification function execution time ?

periodic timer. Restriction on notification function execution time ?

marcrechte — Thu, 19 Nov 2015 13:56:52 GMT

Hello,

I setup a periodic timer whose notification function takes time to process (but less than the timer period).

I wonders whether it is a design fault ?

Thanks

Marc

Re: periodic timer. Restriction on notification function execution time ?

soledad — Thu, 19 Nov 2015 17:39:15 GMT

Hello Marc,

The tick service routine is located in the init_bsp.c file, the path of this file is <freescaleMQXpath>\mqx\source\bsp\<board_name>\

The resolution defines, how often MQX RTOS updates time, or how often a tick occurs. The resolution is usually 200 ticks per second = 5 milliseconds. It is defined in <board_name>.h file located at the path: <freescaleMQXpath>\mqx\source\bsp\<board_name>\

The BSP timer is clocked by system tick; it is possible to edit BSP_ALARM_FREQUENCY in order to have smaller ticks.

Please check more information about the MQX timers in the following document.

Using the MQX timers

I hope this helps,

Have a great day,
Sol

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Re: periodic timer. Restriction on notification function execution time ?

marcrechte — Fri, 20 Nov 2015 06:44:08 GMT

Hello Sol,

Thanks for the information and related document.

However my question is on software periodic timer, especially _timer_start_periodic_every... functions: does the notification_function need to return quickly (like in an ISR) or it is not a problem to do some processing providing it does not exceed the timer period ?

Regards

Marc