Sun Microsystems Ultra 60 Service Manual page 220

FIGURE C-6
C.1.10.2 Diskette Port
The diskette port is supported by a diskette controller, located on the SuperIO ASIC,
and the Cheerio ASIC. The diskette controller is software compatible with the
DP8473, DP765A, and the N82077 diskette controller. The SuperIO ASIC is
compatible with perpendicular recording drives (2.88-Mbyte formatted diskettes) as
well as standard diskette drives. There is a 16-byte FIFO for buffering and support
for burst and non-burst modes. The diskette controller handles data rates of 2 Mbps,
1 Mbps, 500 Kbps, and 250 Kbps.
Note – Sun utilizes the N82077 diskette controller.
There are two extra pins on the Cheerio ASIC that combine with the SuperIO
component-to-diskette drive interface to support all Sun standard diskette drives.
This includes diskette drives that use Density_Select and Density_Sense pins as well
as diskette drives that use a Disk_Change signal. It is DMA driven via a DMA
channel in the EBus interface of the Cheerio ASIC. Auto eject and manual eject
diskette drives (IDs of 0 or 1, respectively) are supported.
C-20 Sun Ultra 60 Service Manual • August 2001
Cheerio
ASIC
Diskette drive
Mode select
Density sense
EBus
Keyboard and Mouse, Diskette, and Parallel Port
Functional Block Diagram
Parallel
port
SuperIO
Keyboard
1
Serial
port
Mouse
2
Diskette
controller
Parallel port
DB-25
EMI
filter
EMI
filter
Keyboard
& mouse
DIN-8
Diskette drive
edge connector