Parallel Port - Sun Microsystems Sun Blade 1000 Service Manual

Two extra pins on the SuperI/O ASIC support all Sun standard diskette drives,
including diskette drives using Density_Select and Density_Sense pins and diskette
drives using a Disk_Change signal. It is DMA driven via a DMA channel in the EBus
interface of the PCIO ASIC. Manual eject diskette drives (IDs of 0 or 1, respectively)
are supported.
Power is supplied to the diskette drive from a separate power connector. 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.
C.1.12.2

Parallel Port

The parallel port is supported by an IEEE 1284-compliant parallel port controller
located on the SuperI/O ASIC. The parallel port controller is a PC industry-standard
controller that achieves a 2-Mbits/sec. (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.
Parallel Port Cables
The parallel port cable is IEEE 1284-compliant and consists of 18 pairs of signal
wires that are double shielded with braid and foil. The maximum length of the
parallel port cable is 2.2 yards (2 meters).
Electrical Characteristics
Drivers operate at nominal 5 VDC TTL levels. The maximum open circuit voltage is
5.5 VDC and the minimum is -0.5 VDC. A logic high-level signal is at least 2.4 VDC
at a source current of 0.32 mA, and a logic low-level signal is no more than 0.4 VDC
at a sink current of 14 mA.
Receivers also operate at nominal 5-VDC TTL levels and can withstand peak voltage
transients between -2 VDC and 7 VDC without damage or improper operation. The
high-level threshold is less than or equal to 2.0 VDC and the low-level threshold is at
least 0.8 VDC. Sink current is less than or equal to 0.32 mA at 2.0 VDC, and source
current is less than or equal to 12 mA at 0.8 VDC.
Appendix C Functional Description C-33