Model 881 8088 Processor Board - IMS 5000 Series Manual

2.4.4 MODEL 881 - 8088 PROCESSOR BOARD
GENERAL DESCRIPTION
The 881 Processor Board is the Central Processing Unit (CPU) of the IMS
International 16-bit systems. The main part of this board is the 8088
microprocessor. The 8088 has an 8-bit data bus interface with a 16-bit internal
architecture. It has 20 address lines, allowing it to directly address up to 1
megabyte of memory. It also has priority vectored interrupt capability. There
are eight levds of vectored interrupts, VIO to VI7; VIO has the highest priority.
The 881 board has a real-time clock circuit (the 58167 chip), which has counters
for tenths of seconds to months.
The I ni tial P rog ram Loader (IPL) EPROM is located on the 881 board. The'
program in this EPROM is executed when the system is powered up or reset.
Ther e is also an option for an 8087 Numeric Data Processor. This increases the
processor's capabili ty f or numerical calculations.
The Model 881 processor consists of a single Printed Circuit Board that normally
occupies the first slot in the Series 5000 or 8000 Computer Systems. It
interfaces with the rest of the system through the address, data, and control
lines of the S -10 0 Bus System.
The hardware on the 881 Processor Board consists of the following fficun
functions.
8088
8087
8259
58167
• 2732
SPEC IF !CATIONS
16-bit Microprocessor (CPU)
Numeric Data Processor{Optional)
Priori ty Vect ored Interrupt Circui tty
Real-Time Clock
4K by 8 bit EPROM
• On-Board ROM:
• Directly Addressable Memory:
• Clock Frequency:
• Circuit Board Dimensions:
Word Size: Address
Data
20 bits
16 bits
4
Kbytes
1Mbyte
4
MHz
5.25" x 10"
IMS International
5000 Series Microcomputers/7.01.83/page 24