AM2634: Resolution in microseconds for timer

Part Number: AM2634

Hello 

I want to measure a execution time of a function. For that reason, I have used in Mcal driver the following functions before and after the function to calculate the timer ticks:

 void Start_Timer(void)
{
    HW_WR_REG32(0x52181000, 0x00000000);//GCTRL
    HW_WR_REG32(0x52181008, 0x00000000);//Capture Control
    HW_WR_REG32(0x5218100C, 0x00000000);//COMP CTRL
    HW_WR_REG32(0x52181010, 0x00000000);//FRC0
    HW_WR_REG32(0x52181014, 0x00000000);//UP Counter
    HW_WR_REG32(0x52181018, 0x00000001);//Compare Up Counter
    HW_WR_REG32(0x52181084, 0x00070F0F);//Clear Interrupt
    HW_WR_REG32(0x52181000, 0x00000001);//GCTRL Start Timer

}

 uint32 Stop_Timer(void)
{
    uint32              frc;
    frc = HW_RD_REG32(0x52181010);
    HW_WR_REG32(0x52181000, 0x00000000);//GCTRL Stop Timer
    return frc;
}

After the tick is calculated; the time is in milliseconds calculated so:

 uint32 Time_MiliSeconds(uint32 Tick_Duration, uint32 Tick_Frequency)
{
    uint32 Duration_ms;
    Duration_ms = (Tick_Duration * 1000) / Tick_Frequency;
    return Duration_ms;
}

the resolution for timer is 1000 Ticks per second, so I get a time in millisecond.

My question is, how can I set the resolution in microsecond?

HW_WR_REG32(0x52181018, 0x000003E8);//Compare Up Counter ---> is this right way ?

hex 348 is in decimal 1000

Thank you in  advance

Best regards