Instruction manual

• JUNKIO Interface:
An interface called the JUNKIO subsystem, which is connected to the
TURBOchannel. The IOCTL ASIC implements this interface. Chapter 7
describes IOCTL ASIC control of the subsystem and Section 9.5 discusses
programming the subsystem, which provides:
A nonvolatile time-of-year clock based on the Dallas Semiconductor DS
1287A Real-Time Clock (RTC)
Four serial lines, through two Zilog SCC (Z85C30) dual UARTS (universal
asynchronous receiver/transmitters)—SCC0 and SCC1.
* Asynchronous for keyboard
* Asynchronous for mouse
* Asynchronous for the printer, through 6-pin MMJ
* CCITT V.24/V.28 19.2 KB/s asynchronous/synchronous 25-pin plug for
communications
An ISDN-S interface, through an AMD 79C30A (Revision E) chip.
Voice-quality audio I/O through the same AMD 79C30A (Revision E) chip,
with a usable bandwidth of approximately 100-3000 Hz.
The audio lines extend from a connector located on the rear of the
enclosure.
Ethernet through an AMD local area network controller for Ethernet
(LANCE) adapter. Both AUI transceiver (thickwire) and 10Base-T
(twisted-pair) interfaces to Ethernet are provided. A setting in the system
support register of IOCTL ASIC selects the interface.
A 32 byte Ethernet address ROM.
Two 256 KB writable console boot ROMs on the I/O module.
Access to eight LEDs, used to display a hexadecimal code for diagnostic
purposes.
The Ethernet, ISDN, audio, printer, and communications ports have DMA
support.
• SCSI Interface:
A dual SCSI interface chip (TCDS), which is connected to the TURBOchannel.
Two NCR53C94 SCSI controller chips that interface to the TCDS ASIC
provide two 5 MB/s 8-bit single-ended SCSI buses, with DMA support.
Chapter 8 discusses the TURBOchannel Dual SCSI ASIC.
1–8 Introduction to the DEC 3000 Models 300/400/500/600/700/800/900 AXP