Bitfields for AMD Am53C974A Target Device Configuration Register:
Bit(s)	Description	)
 15-14	reserved
 13	"FSCSI" Fast SCSI drive is present
 12-8	"SPD" synchronous period
 7-4	synchronous offset (0 = asynchronous transfers)
 3-1	SCSI bus status
 0	target device is present and active
	if 0, all other bits must be cleared to zero for target devices
SeeAlso: #00925,#00927