Sun Microsystems Sun Ultra 60 Service Manual page 194

SuperIO Diskette Drive Interface
The SuperIO component contains an onboard diskette drive controller. There is a
16-byte first-in-first-out (FIFO) device that buffers and supports burst and non-burst
modes. The diskette drive controller handles data rates of 500 Kbps and 250 Kbps.
Supported Features
Two additional pins on the PCIO ASIC combine with the SuperIO diskette drive
interface to support all standard Sun diskette drives. This includes
Density_Select-type diskette drives, Density_Sense-type diskette drives, and diskette
drives that use a Disk_Change signal.
Diskette Drive Connectors
Power is supplied to the diskette drive from a pigtailed connector at the power
supply. The diskette drive operates from a 5-Vdc supply and uses a maximum power
of 1.1 watts during operation. A maximum of 44 milliwatts is used during standby
mode. The diskette drive is connected to the SCSI backplane with a 34-pin ribbon
cable. The maximum cable length is 1.5 meters. From the SCSI backplane, the
diskette drive is cabled to the motherboard with the SCSI connections.
Diskette Drive Signals
Table C–4 lists diskette drive signals by mnemonic name and provides the function.
TABLE C–4
Signal Name
MODE_SELECT
HIGH_DENSITY_IN_L
NDEX
DRIVE_SELECT
Sun Ultra 60 Service Manual ♦ March 1999, Revision A
C-14
Diskette Drive Signals and Functions
Function
When active low, MODE_SELECT sets the
drive for a 1.2-Mbyte formatted disk. When
active high, MODE_SELECT sets the drive
for a 1.44-Mbyte formatted disk.
When active low, HIGH_DENSITY_IN_L
indicates that a high-density disk is inserted
into the drive.
When active, INDEX indicates the beginning
of each track. An active pulse is sent for each
disk rotation.
When set true, DRIVE_SELECT enables the
drive to respond to other input signals.