MEGAHERTZ_ISR
tmp = readb(smc->base+MEGAHERTZ_ISR);
tmp = readb(smc->base+MEGAHERTZ_ISR);
writeb(tmp, smc->base + MEGAHERTZ_ISR);
writeb(tmp, smc->base + MEGAHERTZ_ISR);
readb(smc->base+MEGAHERTZ_ISR);
readb(smc->base+MEGAHERTZ_ISR);