Optron #13 12 июня 1998

Железо

Iron - Kempston mouse.

              Kempston mouse



(C) Rasp,

    Sergey Filimonov


  I sat once at the computer, and safely
yuzal their invaluable mouse - in the "UFO 2" was played. Yuzal 
I yuzal, and suddenly realized what I was a bad man (radish) - 
himself here with all the facilities to play, and the poor

nick forced Claudia trample, playing at the
same "UFO". And I decided then to write in detail in 
"Optocouplers," how can zaimet himself such a convenient device 
like a mouse. Let's start from the beginning.




          Selecting the type of interface



  This has, historically, that
the CIS were extended two
type "mice" interfaces: AY-mouse and
Kemston mouse. Personally, I most likable second of them. Why? 
Yes, because AY-mouse with the simplicity of connecting

has several disadvantages: it is too small bit word origin and 
then that "clings" it directly to AY'ku.

It is appropriate to say that firstly, in
this case being more
danger is so expensive chip as
Music coprocessor, and secondly, how
known to exist interfeys printer
which connects to AY, therefore,
the owners of this devaysa can no longer
connect themselves AY-mouse. And most importantly
- AY-mouse understands too little software. As for the Kempston 
Mouse, what it means, not only domestic but also some 
proprietary software (including including the "Art Studio" - 
the mouse to draw much easier than hand ;))))))). Well

that the same type of interface we have chosen, it's time
he manipulator buy.



            The choice of the manipulator



  As the saying goes, "on the tastes
no. "So take what you are looking for. Dame only a couple of 
tips. Do not buy cheap stuff for 9.7 hryvnia. Why?

Firstly, I venture to recall the proverb
"Miser pays twice." Secondly, I
own experience I know that this mouse is very
difficult and likely impossible to "tame". And third: "It's not 
aesthetically pleasing!" Although ... See above. The most 
viable option - mouse Genius. The mouse must should have three 
buttons: there is a very bad program that love juzat average 
button. Having bought a mouse, be sure to check out it (on PC). 
If something goes wrong, then mouse, bought in a decent 
company, you can exchanged during the week (of course,

if you keep the receipt).

  If you are not very concerned about the appearance of
manipulator and are very concerned about the state of
your purse, you can "pull out" mouse
from any "Corvette" (a computer
a:)) - it will cost you a dime.

  So. The mouse is. You can put it in
aside and do the interface.



             Interface circuit



  The list below is a diagram of my
processing of the other three schemes of the interface -
from each scheme were taken dignity and
dropped faults. Some innovations
were introduced on the advice of T. Nikolaychuk.

  Before the present scheme, make one caveat: if you are not 
able to gather a rather elaborate scheme (do not know how to 
solder, laziness, and once etc.), then you can wait a bit and 
through week or two will be able to buy a brand new

Kempston mouse interface Sergei Filimonov.

  But actually the scheme:



  DD1-DD4 - 561IE11

  DD5, DD6 - 555KP11

  DD7 - 555ID7

  DD8 - 555LP8

  DD9 - 561TM2

  R - 1k


  Decoding mouse ports, and is collected on ID7
a free element of LP8, in this
scheme plays the role of logical addition.

  To calculate the coordinates used reversible four-digit 
counters, combined pairwise to increase the word length to 
eight for each coordinate. For simplicity, consider the plot 
scheme, responsible for counting the coordinates of "X" 
(processing coordinates of the "Y" is carried out similarly).

On the clock input C counters DD1 and DD2 received impulses 
from the optocoupler mouse after shaper. The findings of 10 
(direction accounts) must submit either a logical

"0" when moving the mouse in one direction, either "1" when 
moving back. Idea of ​​T. Nikolaychuk was to put

561TM2 element chip, which will be
grant level "0" or "1" respectively (with the mouse exits Xa 
and Xb, as is known, are rectangular pulses with a delay

quarter period from each other). In previous schemes, the mouse 
on the counter at 561IE11 a similar idea to me (SF) is not 
vstretalas. Impulses traveling to the input direction of the 
mouse is not sosvsem successfully extinguished razlichnymy 
tanks that first, entailed a twitch when the cursor movement, 
and secondly, the inertia occurred when the direction of 
movement at the appropriate coordinate.


  The main advantage Kempson mouse - it
independence of its work from the CPU.
Meters coordinate incremented (decremented) when moving devaysa 
and information from them is read by

KP11 at any time of the program
(Not necessarily an interrupt, it is possible and
less important that the frequency of recourse to
mouse was greater than the frequency of overflows
counters). Here, incidentally, can be seen clearly
advantage over the AY-mouse. Since
last - four-digit, the counter
its crowded into 16 (2 to the fourth power) times more likely, 
therefore, the processor need to AY-mouse 16 times more often!


  Information on the status of the three mouse buttons
issued to the processor through the elements with LP8
third state.



             Alteration of mouse



  If you bought a mouse for their money, then
you must come to terms with one fact -
mouse to surgery.

  Open the mouse pre vynyv
ball, and what we see? .. A bunch of not quite
useful for us detalek. The first step by removing unnecessary - 
a processor (not surprised there are processors and 18-feet, 
and sometimes with 8;)))), quartz, capacitors, transistors. 
Diodes and resistors better not to touch. After such an 
intervention in the mouse should stay: two disks with slits 
with attached rollers, two optocouplers, three "mikrika" under 
buttons and a few resistors. To start the most simple - a 
button. For each button do the following "revision":

Further - more, we need to convert the analog signals,
coming from the optocoupler, the signals
rectangular shape to their
could handle the counters. The right thing would be for this
purpose use Schmitt trigger, but there
one "but": we need a chip 561TL1
(TTL-native elements in this case is not desirable to use), and 
its in our region is difficult to find, and more CMOS vskih 
Schmitt Trigger is not. So I'm doing this: As the inverter is 
used 561LN2 resistor

resistance of the order of 47-51 ohms. In
resulting signal
takes a rectangular shape that
in fact, shown in the figure.

  That's it.



                Conclusion



  If you did everything correctly, you can
to congratulate you - you are the owner of the real Kempston 
Mouse! If suddenly having problems, please call: the

I can - help. Phone in Lviv:
67-60-45, ask Vladimir.

  The next time I'll tell you what is the mouse for the 
programmer and how it cope. And while for the seed ladies only

interface ports:


  # FADF - buttons, bits 0-2;

  # FBDF - coordinate X;

  # FFDF - coordinate Y.



              Post Scriptum



  If your computer has an interface
Kempston joystick (the presence of the manipulator is not 
required), there may be conflicts between the mouse and 
joystick. To eliminate them, I can think of to replace the A5 
in deciphering the joystick on the A6. For "Lviv option" it 
will be 9-I leg D65 (LE1): gently okusyvaem leg

pliers at the board, turn down and connect with the 36 th leg 
of the processor. How to realize such a thing in such 
pathologies as Miko-Best I've already talked to an 8-m 
"Optocouplers.