North Star HRAM-64 User manual

NorthStar^
North Star Computers, Inc.
14440 C ata lina St., San Leandro, C A 94577 USA
(415) 35 7 -8500 TWX/Telex [phone]
HRAM
HORIZON Random Access Memory
USER /TECHNICAL MANUAL
HORIZON is a registered trademark of North Star Computers, Inc.
Copyright © 1981, by North Star Computers, Inc.
All Rights Reserved
00406B

CONTENTS
Section Pag£
1 INTRODUCTION
1.1 General Description 1-1
1.2 Warranty Information 1-1
1.3 Specifications 1-3
2 INSTALLING AND REMOVING THE HRAM
2.1 Installation 2-2
2.2 Removal 2-3
3 IMPLEMENTING HRAM OPTIONS
3.1 Example Memory Configurations 3-3
3.1.1 Example 1: Three Banks 3-3
3.1.2 Example 2: Three Banks 3-5
3.1.3 Example 3s Four Banks 3-6
3.2 Bank Switching 3-7
3.2.1 Designating Switched Areas 3-7
3.2.2 Designating I/O Port Control Bit 3-9
3.2.3 Software Instructions 3-10
3.2.4 Bank Status on Reset 3-11
3.3 Memory Address Switches 3-13
3.3.1 Revision B Board 3-13
3.3.2 Revision E Board 3-14
3.3.3 32K Board 3-18
3.4 First Quadrant Option (Revision E Board only) 3-19
3.5 Parity Checking 3-20
HRAM USER/TECHNICAL MANUAL

Section Page
3.5.1 Designating I/O Port Control Bits 3-20
3.5.2 Designating Parity Error Response 3-21
3.5.3 Software Instructions 3-22
3.6 Board and Schematic Revision Levels 3-22
4 TESTING THE HRAM
5 THEORY OF OPERATION
5.1 Overview 5-1
5.2 Address Multiplexer 5-3
5.3 Refresh Logic 5-3
5.4 Port CO Detector 5-4
5.5 Address Latch 5-4
5.6 Address Decoder 5-4
5.7 Jumper Area JP1 5-5
5.8 Bank and Parity Logic 5-5
5.9 Strobe Generator 5-6
5.10 Voltage Regulators 5-9
6 TROUBLESHOOTING
6.1 Check HRAM Seating 6-1
6.2 Change Board Slots 6-2
6.3 Check HRAM Configuration 6-2
6.4 Run Diagnostic Programs 6-2
6.5 Replace HRAM 6-3
6.6 Repair Procedures 6-3
HRAM USER/TECHNICAL MANUAL

APPENDICES
A RAM Chip Location Chart A-l
B Bus Signals Used by HRAM B-l
C HRAM 64K - Parts List C-l
D HRAM 64K - Schematics D-l
E Reader Response Form E-l
HRAM USER/TECHNICAL MANUAL

INTRODUCTION 1
This manual supplies the user of the HORIZON Random
Access Memory (HRAM) board with information he or she
needs to install the board and put it into operation.
This includes information on selecting the various
memory options, testing the board and resolving any
difficulties associated with system integration.
The manual also provides information for service
technicians and engineers who may wish to evaluate the
technical aspects of the board or to undertake its
repair.
1.1 GENERAL DESCRIPTION
The HRAM board is a random access memory board designed
for use in the HORIZON computer system.
There are three versions of the HRAM board: HRAM-64
with 64K bytes, HRAM-48 with 48K bytes, and HRAM-32
with 32K bytes. The only significant difference
between these boards is the amount of memory they
contain. All three versions incorporate parity error
checking and bank switching capabilities.
1.2 WARRANTY
North Star Computers, Inc., warrants the electrical and
mechanical parts and workmanship of this product to be
free of defects for a period of 90 days from date of
purchase. If such defects occur, North Star Computers,
Inc. will repair the defect at no cost to the
purchaser. This warranty does not extend to defects
resulting from improper use or assembly by purchaser,
nor does it cover transportation to the factory. Also,
the warranty is invalid if all instructions included in
the accompanying documentation are not carefully
followed.
HRAM 1-1 USER/TECHNICAL MANUAL

Should a unit returned for warranty repair be deemed by
North Star Computers, Inc. to be defective due to
purchaser's action, then a repair charge (not to exceed
$50 without purchaser's consent) will be assessed. ANY
UNIT(S) OR PART(S) RETURNED FOR WARRANTY REPAIR MUST BE
ACCOMPANIED BY A DATED COPY OF THE ORIGINAL SALES
RECEIPT. The item should be returned to the dealer
from whom the product was purchased, for implementation
of the warranty. When sending the item to the factory
for repair, the dealer must call the North Star
Technical Hotline to receive a Return Material
Authorization (RMA) number to accompany the item to the
factory.
The following warranty limitation applies to units
located outside the United States of America: All costs
and arrangements for transportation of the product to
and from the factory are borne entirely by the
customer.
No warranty, expressed or implied, is extended
concerning completeness, correctness, or suitability of
the North Star equipment for any particular
application. There are no warranties which extend
beyond those expressly stated herein. This limited
warranty is made in lieu of all other warranties,
expressed or implied, and is limited to repair or
replacement of the product.
HRAM 1-2 USER/TECHNICAL MANUAL

1.3 SPECIFICATIONS
The HRAM specifications are given in Table 1-1.
Table 1-1
HRAM Specifications
Storage
Capacity 32K bytes for the HRAM-32
48K bytes for the HRAM-48
64K bytes for the HRAM-64
Bits per Byte Eight data bits and one parity
bit.
Access Time 300 ns typical
HRAM 1-3 USER/TECHNICAL MANUAL