1.1 System Components and Features
1.1.5 ISA Interface Overview
The ISA bus has two dedicated slots and a third shared ISA/PCI slot. It
provides the following system support functions:
•
Mouse and keyboard controller functions—provided by an Intel 8242 chip.
•
An IDE interface, a diskette controller, two universal asynchronous
receiver–transmitters (UARTs) with full modem control, and a bidirectional
parallel port—provided by a National 87312 combination chip.
•
A time-of-year (TOY) function—provided by a Dallas Semiconductor
DS1287 chip.
•
Operating system support—provided by a 1MB flash ROM that contains
firmware and debug monitor code.
Users can develop code on a host system, and load software into the EB164
through a serial line, diskette, or Ethernet board. In addition, sectors of
the flash ROM can be programmed for application-specific purposes.
1.1.6 Miscellaneous Logic
The EB164 contains the following miscellaneous components:
•
Clocks
A 26.66-MHz oscillator and phase-locked loop (PLL) clock generator provide
a clock source to the 21164 microprocessor and system.
A 14.3-MHz crystal and frequency generator provide a clock source for ISA
devices.
•
Serial ROM
A Xilinx XC17128 serial ROM (SROM) contains initial code that is loaded
into the 21164 instruction cache (Icache) on power-up. A serial line
interface is also provided to allow direct connection to a terminal line for
debugging purposes.
•
Programmable array logic (PAL) devices for the following functions:
One PAL for utility bus (Ubus) decoding
One PAL for interrupts
Two PAL devices for memory row address strobe (RAS) bank generation
and buffering
1–4 Introduction to the EB164
