Minimum period for MQX Timer

[JaimeR]

What's the minimum period suggested for a periodic MQX Timer?

[Jairo]

The minimum timer interval is 1 tick, and it's equivalent to 5ms

[bistrulli]

is it possible to set periodic timer with period less then 5ms?

[Kyle_Apollo]

We got it down to 1 tick = 1mS, by modifying the BSP_tick_frequency in the BSP (dont hold me to that exact name, but it is something to that effect).  By changing it from 200 (default) to 1000, you increase your resolution 5 fold.  To get uS resolution, you have to bypass MQX and use hardware interrupts (at least this is what we were told by our FAE, using the coldfire V1 core). 

[Kafre]

I've been looking for the name of the tick frequency parameter for a while, could you drop me a clue of where to find it, please?

[anthony_huereca]

It's the BSP_ALARM_FREQUENCY parameter, which is set in <mqx_dir>\mqx\source\bsp\<board_name>\<board_name>.h

The ticks are then set up in the BSP initialization, located at <mqx_dir>\mqx\source\bsp\<board_name>\init_bsp.c

    kernel_data->TIMER_HW_REFERENCE = (BSP_SYSTEM_CLOCK / BSP_ALARM_FREQUENCY);       _time_set_ticks_per_sec(BSP_ALARM_FREQUENCY);    _time_set_hwticks_per_tick(kernel_data->TIMER_HW_REFERENCE);    _time_set_hwtick_function(_bsp_get_hwticks, (pointer)NULL);

[bistrulli]

Thank you so much Kyle, I'll try it soon.