IAR PowerPac RTOS User Guide

The following diagram illustrates how low-resolution measurement works. We can see that the section of code actuallybegins at 0.5 ms and ends at 5.2 ms, which means that its actual execution time is (5.2 - 0.5) = 4.7 ms. However witha tick of 1 ms, the first call to OS_GetTime() returns 0, and the second call returns 5. The measured execution timeof the code would therefore result in (5 - 0) = 5 ms.OS_GetTime() => 0 OS_GetTime() => 5Code to be timedOS_Time0.5 ms 5.2 ms0 ms 1 ms 2 ms 3 ms 4 ms 5 ms6 msFor many applications, low-resolution measurement may be fully sufficient for your needs. In some cases, it may bemore desirable than high-resolution measurement due to its ease of use and faster computation time.Low-resolution measurement API function overviewRoutineOS_GetTime()OS_GetTime32()OS_GetTime()DescriptionReturns the current system time in ticks.Prototypeint OS_GetTime (void);Return valueThe system variable OS_Time as a 16- or 32-bit integer value.Additional InformationThis function returns the system time as a 16-bit value on 8/16-bit CPUs, and as a 32-bit value on 32-bit CPUs. TheOS_Time variable is a 32-bit value. Therefore, if the return value is 32-bit, it is simply the entire contents of theOS_Time variable. If the return value is 16-bit, it is the lower 16 bits of the OS_Time variable.OS_GetTime32()DescriptionDescriptionTable 118: Low-resolution measurement API overviewReturns the current system time in ticks.Returns the current system time in ticks as a 32-bit value.Returns the current system time in ticks as a 32-bit value.114IAR PowerPac RTOSfor ARM CoresPPRTOS-2