MFM
#define CMD_READ (MT + SK + FDRAW_RDCMD + MFM)
#define CMD_WRITE (MT + FDRAW_WRCMD + MFM)
csb->csb_cmds[0] |= MFM;
csb->csb_cmds[0] = SK | FDRAW_RDCMD | MFM;
csb->csb_cmds[0] = MT | SK | FDRAW_RDCMD | MFM;
csb->csb_cmds[0] = FDRAW_WRCMD | MFM;
csb->csb_cmds[0] = MT | FDRAW_WRCMD | MFM;
csb->csb_cmds[0] |= MFM;