mcf5206 - interrupt level

[Stan]

hi,

I need to intercept four external interrupts (two ethernet controler, power
fail and modem dcd).
Rtems use Timer1, Timer2, Mbus, Uart1 and Uart2 internal interrupts.

What should be timer1 level (timer1 call rtems_clock_tick directive) ?
Is Timer1 ISR level important ?
It should be greater or lower other interrupts level ?

Thanks a lot.

Stan.