the transactor v1 08 1979 jan 31

8/7/2019 The Transactor V1 08 1979 Jan 31

http://slidepdf.com/reader/full/the-transactor-v1-08-1979-jan-31 1/8

( kcammadare

The TransactorPET i s a registered Trademark of Commodore Inc.

comments and bulletinsconcerning your

COMMODORE PET

BULLETIN #8

January 31, 197

You may recal l l a s t month tha t Chapters 1 through 7 were

included with the Nov./Dec. issue and Chapters 8 through the

appendices were to be included with this i ssue . Well, by now

you ~ r o b a b l y real ize that what you received is the ent i re

PET User Manual. This month, we are enclosing with each

ftTRANSACTOR ft a copy of the User Port Cookbook.

Brief ly , it outl ines the operation of the User Port and wil l

help those in teres ted in terfacers get on t he i r fee t . I don ' t

know who wrote the Cookbook, so i f anyone out there knows the

author ' s name please contact me so I may cred i t him in the

next 110t • - Karl J .



"COI1PUTEF..3-FOR-EVERYONE" Courses

Human Computing Resources (HeR), a Toronto based corpora t ion

looking fonlard to expansion i n g rea t e r Canadian c i t i e s , i s

offer ing a se r ies of courses on computers . Present l ;y , there

a re four bu t HeR i s plarilling more in the fu tu re . Information

i s ava i l ab le on a l l of the courses and can be obta ined f r o ~ V ~ r ~ y Arille Carswel l who has forward to me a b r i e f out l ine fo r

the "TR.';.NSACTOR"

January , 1978

PRESS RELEASE

Human Computing Resources Corporation 10 St. Mary Street, Toronto, OntariO, Canada M4Y 1P9

416-922-1937

COMPUTER COURSES FOR EVERYONE

Human Computing Resources Corpora t ion announces a s e r i e s of

courses on computers .

The courses were crea ted in response to the growing need for anobjec t ive , non sa l e s o r i en ted , viewpoin t on how to evalua te per

sonal computers , microcomputers and minicomputers . They wi l l be

a t t r a c t i v e to people from many walks of l i f e - - bus iness people ,

p ro fe s s i o n a l s , a r t i s t s , en thus i a s t i c new users - - anyone who hasimagined t h a t a computer could make l i f e eas i e r . They w i l l be

doubly a t t r a c t i v e to people who have researched the computer

market an d f ind they l ack the ex p e r t i se to choose one system overano ther .

Ins t ruc to r s are sk i l l ed ed u ca to r s , business people and c rea t ive

computer profe s s iona l s . They have had broad exper ience with a l ltypes of computers an d computer app l i ca t ions .

Planned for the immediate fu tu re are :

In t roduct ion to Personal Computers ( January and March)

In t ro d u c to ry Programming in BASIC (January and March)

Making Computer Music (February 17)How to Buy a Computer for Small Business (February 28)

In the works are courses on microprocessors , e lec t ron ic t roub

l eshoo t ing , programming in PASCAL, computer graph ics , word process i n g , computers in the law o f f i c e , computers in the medicalo f f i c e , and computer-aided a r ch i t ec tu r a l des ign .



A ll courses wi l l be held on the premises of HCR a t 10 S t . Mary

S t r e e t , Su i t e 401, Toron to (near Yonge and Bloor ) , with the ex

cep t ion of the smal l business cour se , which wi l l be held a t theBond Place H o t e l , 65 Dundas S t r e e t Eas t ( j u s t e a s t of Yonge) ,Toronto M5B 2G8, (416)362-6061.

Fees for a l l courses a re income tax de duc t i b l e .

HCR was formed th r ee year s ago , to provide i nd i v i dua l s , indust r i e s and government with c o s t - e f f e c t i v e and responsive computersys t ems . HCR has watched developments in the pe r sona l computerindus t ry with g r e a t i n t e r e s t , p a r t i cu l a r l y because o f i t s convic

t i on t h a t computer use needs to be demyst i f ied and humanized.

For more i n fo rmat ion , c on ta c t Mary Anne Carswel l a t 922-1937 .

T.P.U.G. TAPE LIBRARY

I recently met with Lyman Duggan of the Toronto PET

Users Group and discussed the possibi l i ty of the dealers

offering "The program copying arrangement" instead of Commodore.

We fe l t this would give bet ter exposure. to "the programs" and

make the l ibrary more accessible.

The Club plans to produce C-60's with a number of the

more popular programs and dist r ibute them (a t cost) to any

interested dealer(s) who would, in turn, offer them to customers

at no charge. However, the idea is s t i l l under development.

More detai ls wil l be in the next "TRANSACTOR". Anyone with

enquiries can cal l me a t (416)499-4292.



INTERFACERS ••••

This month I received a l e t t e r from Andrew Hwang of Concordia

Designs in Toronto. Andrew has successfully interfaced a PET

to an X-Y Plot ter . E x c e l l e n t ~ A copy of his response follows.

Thank you Andrew.

anyone else has gizmos or gadgets interfaced to thei r

be it pract ical or unusual, write in and t e l l us about i t ~ A brief note is suffic ient (such as Andrew's), and businessess •••

the "TRANSACTOR" is sent to over 500 subscribers.

Get the hint?

INNOVATIVE

CUSTOM DESIGN

SPECIALISTS

ING :JIV

P.O. Box 219, Sta t ion D, Scarborough, Ontar io , Canada. MIR 5B7

CPU Club Ii.embers

c/o Commodore business f'lachines .Ltd.3370 Pharmacy i\.ve., i;gincourt,C N T ~ r l I C . 2h4

r l ~ : Full Graphical Plott ing Capabilitywith the P.c;T and a :Jigital Plot ter

Dear Fellow CPU Members:

e have succeeded in interfacing the

.:Jec.

Plotter by Houston Instruments. l < ~ u l l hard-co

of data or functions can now be easi ly plottedaccuracy of up to 0.005 inches. :3 oftwares are 0 eva ito issue plot t commands in simple basic steps. Anyone i3hingmore information may write to: Concordia :Jesigns, Interfacing Div.,P.G.Box 219, ~ t a t i o n J, ~ c a r b o r o u g h , Ontario, Canada. 5B7.

Faithful ly,

Iilr. Andrew HwangP ~ T User Club Member



HARDWARE FIX

Most PET Users involved with data f i les are aware of the problem

concerning f i le reads. That is af ter a block READ the tape motor

does not stop instantaneiously and tends to ro l l the tape past

the beginning of the next block result ing in 'LOST DATA'.

Realizing th is , Richard Leon and Larry Phil l ips of the Vancouver

PET Users Group devised a hardware f ix . I t consists of a resis tor ,

a capacitor, a diode and the unused half of the DPDT switch

connected to the record button of the casset te deck (Figure 1).

\ ) N ~ ~ A \ . F ~ c o n : p

\3U"T-rd>N

S W I T ~

t5,000 ,.P-'Tcl. ZOv

G { ' t o ( ) ~ ) : > iJ--..-------"'------------



Operation is re la t ive ly simple. During Data writes the record

switch is closed and the capacitor charges through the res is tor .

When the block i s finished the motor voltage turns off and Cl

discharges into the motor through the diode causing the armature

to rotate tha t extra l i t t l e bi t . This allows a larger gap

between blocks. During reads, the motor s t i l l does not stop

instantaneously but i t won't ro l l far enough for the tape head

to encounter the next block. (During reads the record switch

is up and the charging network is disabled).

The f ix i t s e l f poses only one problem. Ins ta l la t ion. Many of

you may not be will ing to dismantle your casset te decks to

access the record button DPDT switch. Therefore I have a second

idea. Using the same concept as Richard Leon, build an

'INTERFACE' for your tape deck and ins ta l l it between the 6 pin

molex plug and the printed ci rcui t board edge connector.

The same ci rcui t ry is used with one major difference. The enable/

disable switch must be simulated such that identical operation

is obtained without using a mechanical switch. Therefore the

swtich needs control logic such that i t enables the c i rcu i t

during data writes and disables i t during reads. Ideal ly , this

could be done with logic gates, however most TTL logic chips

require +15 and -15 vol t supplies . There is "logic" available

on the PCB cardedge. Here are the characterist ics:

PIN OPERATION

o ~ d ~ ~ B Ir.ar [Q:E

NONE READ WRITE

READ Low Active Active

WRITE High High Active

SENSE High Low Low

MOTOR Open 6.5v 6.5v

(floating)



Using these l ines a control must be designed to ei ther

open the switch during reads or close it during writes . This

is where I stand r ight now. The 'wri te ' l ine seems to be the

most l ikely candidate for the control input since 'wri te ' i s

held high constantly and goes low only during writes . Therefore

i t could be used to hold open a N.C. (normally closed)switch.

However, when data i s passed to the tape, 'wri te ' is active

(high and low) which means the switch will be on, off or

unstable anyways.

I f this signal could be ' f i l te red ' and seen by the

switch input as low during writes the switch would stay closed

and the design is complete. Here's what I have so far . Will

it work?

Karl J.

~ n c u ~ G - - ~ - - - - - - - - ~ - - - - - - - - - - - - - - - - - - - - - - - - ~

* N.C. integrated switch. Part number anyone?

the transactor v1 08 1979 jan 31

Documents