Microengine WD/90 Pascal User manual

WD/90
Pascal MICROENGINETM
Reference Manual

THE tlICROENGlNE COMPANY
til
Pasca1 MICROEHGINE Computer
User's Manual
PreliMinary Edition
March, 1979

Software is provided on a licensed basis only and is the property of the
University of California with per.issil:m granted for use on an individual
systeM basis only. Copies may be made for archival purposes only.
Infor.ation furnished by The nICROENGIIE Company is believed to be accurate
and reliable. However, no responsibility is assumed by The tlICRDENGINE
Company for its use; nor for any infringements of patents or other rights of
third parties which Ilay result fr:;),. its use. No license is granted by
implication or o'ther",ise under any pat-ent or patent rights of The MICRDENGIME
COIlPany. The MICRDEHGlNE COIIPanl~1 reserves the right to change product
specifications at any time without notice.
Copyright (c) 1979 ib~ The MICROENGlHE Company
First Prillted March 1979
All l'igl:ts reserved.
No part of this dOt:ulll£rnt may be reproduced by
any
Eans, nor "t;raT,slated, nor tranSlAi tted
into amachine lal1guil ge without the written
permission of The 11ICJi~OEMGlME COlRpany.
MICROEHGlNE is aR€,gistered Trademark of
Yestern Digital Co'rpol'ation.
The
MICROENGlHE 'Company is awholly··mvned
subsidiary of YestE?rn Digital Corporation.

PREFACE
This manual describes the use and operation of the MICROEMGINE Company's
microcomputer products for developing and executing programs in the Pascal
language. These products are:
o the UD/900 Pascal MICROENGINEtm Single-Board Computer,
an a by 16-inch board containing a WD/9000 16'-bit
microprocessor that directly executes UCSD's Pascal P-
code,
64K bytes of memory, 2 RS-232 asynchronous serial
ports, 2 a-bit parallel ports, and aFloppy Disk
Controller,; and
o the WD/90 Pascal MICROENGINE Computer, adesktop
microcomputer comprised of aPascal MICROENGINE Single-
Board Computer and pa.er supplies enclosed in a
stylized housing.
The' lRanua lis intended to serve both as an introductoryguide and as a
reference source. Chapter 1 presents an overview of the computer. It briefly
describes hardware components of the computer; the software provided with the
computer; the mechanical, environmental, and electrical requirements of the
cOIIlputer,; and the computer operation. Chapters 2, 3, and 4provide "how-to"
infbrmation: how to install a new computer, how to operate the computer, and
how: to perform troubleshooting procedures. Chapter 5 presents detailed
infbrmation on the computer's operation.
The' software provided with the computer is the Pascal Operating System
developed at the University of California at San Diego (UCSD). This operating
system is described in the Pascal 111.0 Operating System Reference 11anual.
ItIHBB!
This manual was prepared and edited using the
UCSD Pascal Screen Oriented Editor and was
printed using a PRINTRONIX Model P300
lineprinter. The lineprinter was provided by
PRINTROMIX Corporation, Irvine, California.

CONTENTS
1.
O'JERVIEtJ ••••••••••••• "" II " II It III " " •• II " • III • " ... III " " III III "III III II •• II " II III III II " II a _ " •• " " • III "
1.1 Components of the Coaputer ••••••••••••••••••••••••••••••••••••
1.2 Pascal Operating System •••••••••••••••••••••••••••••••••••••••
1.3 Requirements of the Computer ••••••••••••••••••••••••••••••••••
1.4 Computer Operation •••••••••••••• ~ •••••••••••••••••••• _ ••••. a ••
1
1
2
3
3
5
5
INSTALLATION PROCEDURES ••••••••••••••••••••••••••••••••••••••••...•••
2.1 Setting Option Switches •••••••••••••••••••••••••••••••••••••••
2.1.1 Opening the Computer Housing ••••••••••••••••••••••••••
2.1.2 Setting the Floppy Disk Controller Option
Switches
••••••••••••••••••••••••••••••••••••••••••••• 7
2.1.3
Setting the System Terminal Specifications
Switches ••••••••••••••••••••••••••••••••••••••••••••• 8
2.1.4 Setting the Serial Port Baud Rate Switches ••••••••••• 10
2.1.5 Reclosing the Computer Housing ••••••••••••••••••••••• 10
2.2 Installing System Components •••••••••••••••••••••••••••••••••• 11
2.2.1 Installing the Computer •••••••••••••••••••••••••••••• 11
2.2.2 Connecting the Peripherals ••••••••••••••••••••••••••• 11
2.2.3 Plugging in the Power Cord ••••••••••• ..,••.., 12
OPERATING PROCEDURES •••••••••••••••••••••••••••••••••••••••••• ~ ••••••
3.1 Starting and Stopping the System ••••••••••••••••••••••••••••••
3.1.1 Turning On the Power •••••••••••••• a ••••••• ~ ••• # ••••••
3.1.2 Loading the System Software ••••••••••••••••••••••••••
3.1.3 Stopping the System ••••••••••••••••••••••••••••••••••
3.2 Changing Hardware Option Switch Settings ••••••••••••••••••••••
13
13
1:"
14
11.1
15
17
17
18
18
TROUBLESHOOTING PROCEDURES •••••••••••••••••••••••••••••••••••••••••••
4.1 The Troubleshooting Process: AGeneral Discussion •••••••••••••
4.2 Symptom 1: Operating System Fails to Announce Itself ••• 4 ••••••
4.2.1 Repeating the Software Loading Procedure •••••••••••••
4.2.2 Checking the Floppy Disk Controller Option
Switches
••••••••••••••••••••••••••••••••••••••••••••• 18
4.2.3 Measuring and Adjusting the Power Supplies ••••••••••• 19
4.3 Symptom 2: Transfers to the System Terminal Fail •••••••••••••• 20
4.4 Symptom 3: Transfers to the Parallel Ports Device or
Floppy
Disk Fail ••••••••••••••••••••••••••••••••••• 21
4.5 Symptom 4: System Fails to Pass Diagnostic Program •••••••••••• 21
4.6 The Troubleshooting Process: a Summary Flow Chart
4.
5. THEORY OF OPERATIONS ••••••••••••••••••••••••••••••••••••••••••••••••• 25
5.1 Processor/Memory and Processor/Peripherals Communication ••••••• 25
5.1.1 Processor/Memory Communication •••••••••••••••••••••••• 28
5.1.2 Process-ot'-Initiated Communication with Peripheral
Devices ••••••••••••••••••••••••••••••••••••••••••••••• 28
5.1.3
Device-Ini tiated Communication with the Pt'ocel:.sor
Interrupts •••••••••••••••••••••••••••••••••••••••••••• 29
5.2 Pascal MICROENGINE Processor ••••••••••••••••••••••••••••••••••• 30
5.3 I1efttory "' D •• '" II ". 31
5.4 Sel'ial Ports ••••••••••••••••••••••••••••• a ••••• __ •• _ •••••••••••• 31

5.4.1 Default Operation of the serial Ports •••••••••••••••••••••
5.4.2 Device Programmin9 Me'chanism: the Control Registers •••••••
5.5 Parallel Ports ••• a ••• 4." •••••••••••••••••••••• ~ •• U ••••• M.~ ..
5.5.1 Default Operatil)n (If the Parallel Ports •••••••••••••••••
5.5.2 Device PrograMing Mechanism: the Control Regj.ster •••• u
5.6 Floppy Disk Controller and DtlA Controller .
5.6.1 Start-Up ProcedlJre~, Involving the DMAC and Fl)C- n QO .
5.6.2 Processor-Initi,~te(1 Communication with the DtlAC and FOC.
5.6.3 DMA Controller Orgcmization and Operation .
5.6.4 Floppy Disk Con'tro:.ler Organization and OperatiOlI .
ILLUSTRATIONS
FigUT'le
Number Title
33
37
43
4~:J
46
49
51
51
53
58
1-1
Pascal MICROEMGIME Computer ........................................... ., ..
1
2-,,1 Removin9 the Rear Panel ••••••.•••• wa ••• a.rI." ••• u •••••• 5
2-2 Removing the PC Board ••••••••. · •••••••••••••• 8 ••• _ •• ~#.............. 5
2--3 Location of the Option SlUi t,ch Pack ages 6
2-,,4 Ai r Vents n " " .. ,. ".. _ .0 11
2'-~) Rear Pane1 a- " •••• " •••• " " •• ' " " • " •• " .-" • " • " " " " " " •• "" • " " • " " • '" II " " " • "" 11
3-1 ON/OFF Switch 13
4-1 RESET Button Location •••••••• I1 •••••••••••••••••••••••••••••• u •••••• 19
4-2 Locations of the Power Supp lie!~ «........ 1£/
4-3 Measuring and Adjusting a Powel~ Supply 20
4-4 Fault-Finder Flow Chart , r~ 22
5-1 Pascal MICROENGlNE COMPuter C~nponents ••••••••••••••••••••••••••••• 26
5,-2 Default Parallel Port Control I~egister Values 48
5-3 Format of First Data Word Tran';mitted to the FOe 53
nOLES
Table-
Number
Title
2-,1 Floppy Disk Controller Option Switch Settings PO...... 7
2-2 Standard System Terlllinal SUlitch Settings................................. 8
2-3 System Terminal Specifications Switch Settings 9
2-4 Serial Port Baud Rate Switch Settings 10
5-1 Communication Bus Structure' Control Lines 27
5-2 Standard General Device Addresses 29
5-3 Interrupt Conditions and Ve~ctor Addresses «.................. 30
5-4 Serial Port Cable Connector' Pin Assignments H 32
5-5 Serial Port Addresses ••••••• ~ •••••••••••••••••••••••••••• # •••••••••• 34
5-6 Serial Port Status Register' contents 35

5-7 Serial Port Control Register 1Contents ••••••••••••••••••••••••••••• :37
5-0 Serial Port Control Register 2Contents ••••••••••••••••••••••••••••• 41
5-9 Serial Port SYN, OLE, and Control Register Addresses •••••••••••••••• 42
5-10 Parallel Port Cable Connector Pin Assignments ••••••••••••••••••••••• 44
5-11 Parallel Ports Control Lines (Port C) ••••••••••••••••••••••••••••••• 45
5-12 Parallel Ports Addresses 46
5-jl3 Parallel Ports Control Register Contents •••••••••••••••••••••••••••• 47
5-14 Floppy Disk Cable Connector Pin Assignments ••••••••••••••••••••••••• 50
5-15 DMACIFDC Addresses ••••••••••••••••••••••• ~.G ••••• « ••••••••••• R •• •••• 52
5-16 DMAC Control Register Contents •••••••••••••••••••••••••••••••••••••• 54
5-17 DMAC Status Register Contents ••••••••••••••••••••••••••••••••••••••• 55
5-18 Stepping Motor Rates for FOC Type I Commands •••••••••••••••••••••••• 59
5-19 FDC Command Register Values for Type I Commands ••••••••••••••••••••• 60
5-20 FOC Status Register Contents for Type I Commands •••••••••••••••••••• 61
5-,21 FOC Command Register Values for Type II Commands •••••••••••••••••••• 63
5-22 FOC Command Register Values for Type III Commands ••••••••••••••••••• 64
5-23 FDC Status Register Contents for Type II and Type III
Commands •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 64
5-24 FDC Command Register Values for the Force Interrupt Command
(Type IV) ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 65

1. OVERVIEW
The WO/90 Pascal MICROENGINE Computer is adesktop microcomputer for
developing and executing programs in the Pascal language. Figure 1-1 shows the
out~ard appearance of the computer.
Figure 1-1. WD/90 Pascal MICROENGINE Computer
To create acomplete computer system, the user need only add asystem
terminal, floppy disk drive, and any other desired 1/0 peripheral devices.
Thi!:; introductOl'y chapter prOVides an overview of the hardware
components of the computer; the software provided with the computer; the
mechanical, environmental, and electrical reqUirements of the computer; and
the computer's operation. Subsequent chapters describe procedures for using
the computer and also provide detailed information on the operation of the
compu'l.,;er and its components.
1.1
COMPONENTS OF TIiE COl1PUTER
The WO/90 Pascal MICROENGINE Computer is driven by Western Digital's WO/9000
Pascal MICROENGINE chip set, a stack-oriented 16-bi tprocessor that directltJ
execlltes UCSD's Pasca1 P·~code. The processor and the o·t;her hardwcH'e
comJ)onents of the computer are on an 8 by 16-inch board enclosed in alow-
profile (5-1/4 by 16-1/4 by 13-1/2 inch) stylized housing.
Page 1

The '"'0/9000 processor is ahardware realization of UCSO's pseudo P-machine.
The J)rocessor is cOilprised of fivt? U:I/MOS circuits, each contained in a 40-
pin package. The individual circuit!. are:
oThe Data Chip, containing the RI1cro1nstruction dl¥=oder,
the arithmetic and logic un:Lt <AlU>, and the register
file.
oThe Control Chip. conta1ninfl the lIIacroinstruction
decoder. portions of the control circuitry, the
microinstruction counter, ancl input/output control
logic.
oThree 22 by 512-bit MICROI'I f:hips, containing processor
microinstructions.
The plrocessor uses 4power supplies (+~iV, +12V, -12V, and-5V) and runs off a
3
MH;z clock signal that is subdivided into 4nonovel"lapping phases (75
nanoseconds per phase). All I/O <signa Is are cOl'lpatib Ie 1111 th tl'ansistor-
transistor logic (TTL).
In addition to the five processor clhipH, the board contains:
o64< bytes <321< I/Ords) of ra'ndon-access memory (RAM>.
o Two RS-232 asynchronous serj.al ports lIIith switch-
selectable baud rates fr'lJIIII 110 to 19,200 bits per
second.
o Two 8-bit parallel ports.
oAFloppy Disk Controller that :lS switch-selectable for
single or double-density 5--1/4 or 8-inch floppy disks
and which can control up to 4 drives of the same type.
The Floppy Disk Controller l>perates under control of
the Direct Mealory Access Contrlll1er.
1,,2 PASCAL OPERATING SYSTEM
The software prOVided with the Pa~Kal MICROENGINE Computer is the Pascal
Operating System developed at the University of California at San Diego
(UCSO)" This operating systeRI include':,:
oA Pascal COlllpiler.
oA BASIC Coepiler.
oA File Manager.
oA Screen-Qriented Text Editol'.
oADebugging System.
Pal}E' 2

The operating system is available in any of the following forms:
o One a-inch single-density floppy disk.
o One a-inch double-density floppy disk.
o Two 5-1/4-inch single-density floppy disks.
o Two 5-1/4-inch double-density floppy disks.
Chapter 3 of this manual describes the procedures for loading the operating
system into the computer. Complete information of the use of the operating
system is provided in the Pascal 111.0 Operating System Reference Manual.
1.3 REQUIREMENTS OF THE COMPUTER
The Pascal M1CROENGINE Computer has a straight forward set of easily satisfied
requirefftents:
o The computer requires a flat. hard surface to hold the
board enclosure. which is 5-1/4 inches high. 16-114
inches wide. and 13-1/2 inches deep.
o The computer can operate in temperatures in the range
0-50 degrees C. Humidity can range between 0% and 95%
without affecting the computer's operation.
o The computer normally runs on 110 volts AG. Optionally.
the user can order aPascal M1CROENGINE Computer which
runs on 220 volts At. In either case. the line frequency
range is 48-63 Hz.
1.4 COMPUTER OPERATION
Communication between components of the computer -- processor. memory.
peripheral ports. and controllers -- is achieved via a processor-controlled
bus structure. This structure is comprised of an address bus and latch. a
bidirectional data bus. and several control lines.
The processor initiates communication with a peripheral device or a location
in meaory by loading the appropriate address onto the address bus.. A
peripheral device can initiate cOMmunicaton with the processor by generating
an interrupt. Memory cannot initiate communication with the processor; all
processor-memory communication is initiated by the processor. In addition. the
Floppy Disk Controller operates under control of the Direct Memory Access
Controller. allowing data transfers between afloppy disk and memory without
involving
the processor. Each of these communication mechanisms is disclJssed
in Chapter 5. ,
Page 3

2. INSTALLATION PROCEDURES
When a new Pascal MICROEHGlHE Computer is received, the first step is to
unpack the components and veriry that all or the items listed on the packing
slip have been included and are intact. (In the event that any of the
components are missing or have been damaged in shipping, cont.act your
MICROENGINE Company representative immediately.)
After verifying that the delivery is in order, take the steps outlined in this
chapter to install the computer.
2.1 SETTING OPTION SWITCHES
The Pascal MICROENGINE Computer provides switches for specifying the
chal'acteristics of the floppy disk containing the Pascal Operating System, for
providing inrormation about the system terminal, and for selecting the baud
rate for each of the two serial ports.
2.1.1
Opening the Computer Housing
The first step is to open the computer housing. Begin by turning the computer
on its side with the ON/OFF switch toward the top. (CAUTION: the computer
housing has sharp edges.
Be careful not to scratch your table top.) Remove
the four screws located on the rear panel as illustrated in Figure 2-1.
Slide the rear panel and attached PC board about half way out as illustrated
in lFigure 2-2.
Figure 2-1. Removing the Rear Panel Figure 2-2.
Removing the PC Board
Page 5

X14
FLOPPY DISK
CONTROLLER
OPTION SWITCHES
L9
SYSTEM
TERMINAL
SPECIFICATION SWITCHES
81
1
.. ...1 _4-l..-J--I'_...L.-.1
SERIAL PORT
BAUD RATE
SWITCHES
8
7
6
X16 1--..;;5_1........-
4
3
2
1
IJ
_ .. _-----_._-'--.
=
=
=
=
=
=
=
=
=
r::::::J
=
=
=
=
=
[::::::JC::::::J §
=
=
=
=
=
",,=
~ ~o§
~ ~CX:I~
r---l ~~~~
~ ~oa:=
~ F"""'1 utb::.:5
~ ~Eca:~
0=
OOCJ CJ CJ~ l~
E::::::::J C::J C:::::::J
Fi9Ul'e 2-3. Location e,f the Option Switch Packages
Pa.'~ 6

2.1.2 setting the Floppy Disk Controller Option Switches
Locate the Floppy Disk Controller option switch packa.Qe (component
designation L9) on the board as shown in Figure 2-3.
Th:ls package contains two switches. Switch S1 OFF corresponds to sin91e"
densi ty model and sllli tch 1 ON corresponds to d()ub le-densi ty mode. Swi tch S~!
OFF corresponds to a-inch disksl and switch 2 ON corresponds to 5-'1/4-inch
di!:.ks.
Set these switches according to t~e characteristics of the floppy disk(s)
containing the Pascal Operating System. Table 2'·'1 summarizes the possibll~
combinations of disk characteristics and the cor~espoodin9 option switch
settings.
Table 2-1. Floppy Disk Controller Option Switch Settj.ngf;
Operating System Resides On:
a-inch double-density disk
a-inch single-density disk
5-1/4-inch double-density disks
5'-1/4-inch single-density disks
Set Sl to: Set 82 to:
ON OFF
OFF OFF
ON ON
OFF OM

2.1.3 Setting the System Terminal Spl?cHications Switche~,
After setting the Floppy Disk Controllel' option switchesl the next step is to
provide some information about the sy·~tem terminall i.e.) t·he terminal to be
used as the vehicle for communication bt~tween the computeT' and t·he user. ,)
harduJcH'P. option switch package (Xl4) is provided for supplyi,ng this
inforlllat:ion, located as shrnPn in FiQuT'e 2-3.
Ei.Qht suai tches are provided.
Set these s\uitches according to the cha"'i:lcteristics of the system terminal.
Table 2-2 outlines the settings fo:' a standard system terminal: Table 2··3
describes the function of each switch. The controls on the systelll terminal
must be set to inhibit parity gen.~ration <Operating System constraint).
Switches S7 and S8 must be set to match the number of bits per character
generated by the terminal.
Table 2-2. Standard Systt?m Terminal SUlitch settings
Switch
Setting
._._~ .. "_._- ..
-_._ .... - .. _--
51 1
("OFF"
or
"OPEN")
S2 0
(liON"
or
"CLOSED")
53 0
("ON"
or "CLOSED" )
54 1("OfF" or
"OPEN")
S5 Don't l:are
56 1("OfF"
or
"OPEN")
S7
x
(8i ts I)er
character;
lIlust
S8
ymatch
ietting on terminal. )
PARITY MUSl BE TUR:'!EO OFF AT TERMINAl..
PagE' 8

Table 2-3. System Terminal Specifications Switch Setting!,;
Switch
51-3
54
S5
56
Function
Select the transmit and receive clock:
S:i S2 Sl
00 0 -Transmit and
receive clock input:
(lX)
001-Rate 1(32X)
01o - Rate 2
C32X)
011-Rate 3
(32X)
10o - Rate 4
(32X)
1.
01-Rate 4 - 2
(64X)
11o - Rate 4 - 4
(128X)
111 - Rate 4 - 8
(256X)
In asynchronous mode (switch 6=0) I contr'ols tIl£>
alternate Receiver clock rate:
o - Receiver clock rate determined by
switches 1-3.
1 - Receiver clock rate =Rate 1.
In synchronous mode (switch 6=1), controls SYN
character stripping:
1 - 5YM character stripping enabled.
o - gYM character stripping disabled.
Controls Illhether parity is odd or even:
1 - odd parity.
o ... even par i ty.
Control~ the character mod£>:
1 -- synchronous mode.
o - asynchronous mode.
S7-8 Select the number of bits per chi:lri:lctel':
58 87
o 0·- 8 bits.
o1 - 7 bits.
1 0 - 6 bits.
1 1 - 5 bits.
where: "0" corresponds to "ON" or "CLOBED"
"1" corresponds to "OFF" or "OPEN"

2.,1.4
Setting the Serial Port BalJd .~ate Switches
Locate the serial port baud rate selection switch package (X16) on the board a~·
shown in Figure 2-3.
Four switches are provided for each serial port, allowing 16 possible rate
selections for each port.
Set the 5IIi tches for each seria I port ~;o the baud rates appropriate to the
type of device to be connected to tha~; port. Table 2-4 outlines the settings
for commonly-used baud rates.
Table 2-4. Serial Port Baud Rate Switch Settings
Baud Rate
Switch Settings
Port A Port B
:t 2 3 4 5 6 7 8
50
75
110
.134.5
150
300
600
1200
1800
2000
2400
3600
4800
7200
9600
19200
o000
;[ 000
o1 0 0
I1 0 0
() 0 1 0
:, 0 1 0
() .1 1 0
:l 1 1 0
000 1
L0 0 1
010 1
.l 101
I) 0 1 .1
L 01.1
I) 1 1 1
L 1 1 1
000 0
000 .1
001 0
001 1
o1 0 0
o1 0 1
o1 1 0
o1 1 1
1
000
100 1
1 0 1 0
101 1
1
100
1 101
1 110
111 1
where: "0" correspo',ds to "ON" or "CLOSED"
"1" correspo"ds to "OFF" or "OPEN"
Rec losi ng the Computet' Housi n~
The cotnputer housing can be rec losed by reversing the steps outlined in
subsection 2.1.1. Slide the PC boa':-d and rear panel back in place and then
attach the rear panel by replacing the four screws.
Pag,? 10