Timer Period not correctly

Ok, I tried to do it like this:

        // set on shot time
        IOWR_ALTERA_AVALON_TIMER_SNAPL(HIRES_TIMER_BASE, 0x03E8);
        IOWR_ALTERA_AVALON_TIMER_SNAPH(HIRES_TIMER_BASE, 0x0000);
        // Start timer, single, with IRQ
        IOWR_ALTERA_AVALON_TIMER_CONTROL(HIRES_TIMER_BASE, 0x0005);

and then also like this:

        // set on shot time
        IOWR_ALTERA_AVALON_TIMER_SNAPL(HIRES_TIMER_BASE, 0x03E8);
        IOWR_ALTERA_AVALON_TIMER_SNAPH(HIRES_TIMER_BASE, 0x0000);
        IOWR_ALTERA_AVALON_TIMER_PERIODL(HIRES_TIMER_BASE, 0x03E8);
        IOWR_ALTERA_AVALON_TIMER_PERIODH(HIRES_TIMER_BASE, 0x0000);
        // Start timer, single, with IRQ
        IOWR_ALTERA_AVALON_TIMER_CONTROL(HIRES_TIMER_BASE, 0x0005);

always with the same behavour, about 6 to 8us until the IRQ is served....

In the data sheet it is written on the control register bit CONT:

"When the counter reaches zero, it reloads with the value stored in the period registers, regardless of the CONT bit"

Thus I would assume that with the second shot the time should be right?

Also a test with writing a 7 to the Control register witch also enables the CONT bit (continuous) just "activates" the IRQ just once and not every 1000ms???

Is there maybe a problem with the period setting in QSYS?

=> Set to 1us assuming the timer decrements every 1us meaning with 1000 set to period/snapshot register counter reaches 0 at 1ms.