static uint32_t pwm_isr(cyg_vector_t vector, cyg_addrword_t data)
{
    static uint32_t pwmisr, icnt;
    CYG_INTERRUPT_STATE istate;

    CYG_ASSERT (CYGNUM_HAL_INTERRUPT_PWMC == vector, "Wrong interrupts");
    pwms_idisable;	// mask pwm interrupts
    HAL_READ_UINT32(AT91_PWM + AT91_PWM_ISR, pwmisr); // clears pwm-interrupt
    HAL_QUERY_INTERRUPTS(istate);	// supervisor mode - interrupts are disabled
    HAL_ENABLE_INTERRUPTS();		  // turn them on to allow higher priority irs
    icnt++;							          // to come through
    while (pwmisr) {
    		if (icnt == 1) {
    			if (pwmisr & 7) {	// pwm0..2 run synchroneously, hence only pwm0 has been set for interrupts
    				Set_LEDs();
    				Chk_Keys();	// Check if any key is pressed
    			}
    			if (pwmisr & 8) {	// pwm3 interrupt
    				pwm3d.ticks++;
     				Read_AT91adc();
    				Do_Scan();
    			} // end pwm3 interrupt
            	} // end if icnt
    		else {
    			icnt = (icnt + 0);	// just for the debugger
    		}
    		HAL_READ_UINT32(AT91_PWM + AT91_PWM_ISR, pwmisr); // clears pwm-interrupt
    		if (pwmisr & 0xf)
    			icnt = (icnt + 0);	// just for the debugger
	} // end while pwmisr
	icnt--;
	HAL_RESTORE_INTERRUPTS(istate);	// turns interrupts off again
  cyg_interrupt_acknowledge(vector);	// write eoi to AIC
  pwms_ienable;					// unmask pwm interrupts and leave all the rest to ecos
  return CYG_ISR_HANDLED;
} // end pwm_isr