Diskette Port; Parallel Port - Sun Microsystems Ultra 80 Service Manual

C.1.9.2

Diskette Port

The diskette port is supported by a diskette controller, located on the SuperIO ASIC,
and the PCIO ASIC. The diskette controller is software compatible with the DP8473,
DP765A, and the N82077 diskette controllers. 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 uses the N82077 diskette controller.
There are two extra pins on the PCIO 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 PCIO ASIC. Auto eject and manual eject diskette
drives (IDs of 0 or 1, respectively) are supported.
Power is supplied to the diskette drive from a separate connector pigtailed from the
power supply. The diskette drive operates from the 5-VDC supply and draws a
maximum power of 1.1 watts operating and 44 milliwatts in standby mode. The
diskette drive is connected to the SCSI backplane with a 34-pin ribbon cable.
Maximum cable length is 1.6 yards (1.5 meters). From the SCSI backplane, it is
cabled to the motherboard with the SCSI connections.
C.1.9.3

Parallel Port

The parallel port is supported by an IEEE 1284-compatible parallel port controller
that is located on the SuperIO component. The parallel port controller is a
PC-industry-standard controller that achieves a 2-megabits per second (Mbps) data
transfer rate. The parallel port controller interface supports the ECP protocol as well
as the following:
Centronics – Provides a widely accepted parallel port interface.
Compatibility – Provides an asynchronous, byte-wide forward
(host-to-peripheral) channel with data and status lines used according to their
original definitions.
Nibble mode – Provides an asynchronous, reverse (peripheral-to-host) channel,
under control of the host. Data bytes are transmitted as two sequential, four-bit
nibbles using four peripheral-to-host status lines.
-22 Sun Ultra 80 Service Manual • March 2000