AR_ISR
REG_WRITE(ah, AR_ISR, isr);
REG_READ(ah, AR_ISR);
isr = REG_READ(ah, AR_ISR);
isr = REG_READ(ah, AR_ISR);
isr = REG_READ(ah, AR_ISR);
REG_WRITE(ah, AR_ISR, isr);
(void) REG_READ(ah, AR_ISR);
REG_WRITE(ah, AR_ISR, ~0);