fdp1_read
int_status = fdp1_read(fdp1, FD1_CTL_IRQSTA);
cycles = fdp1_read(fdp1, FD1_CTL_VCYCLE_STAT);
ctl_status = fdp1_read(fdp1, FD1_CTL_STATUS);
hw_version = fdp1_read(fdp1, FD1_IP_INTDATA);