multiple instances of object in an object

Owen · 2007-03-09 18:21

HI
is there any way to use two instances of Full Duplex Serial called from seperate objects without them conflicting? I have FDS runing in my top level object to comunicate with a host pc and then in another object I want to call FDS to comunicate with a controller peripheral. This will want to use the smae variable space in both instances of FDS right? Is there anyway to us an array of FDS objects and call one of them from another object other than the top level where the array of FDS would be created? Maybe I'm missing an easy solution here.

Thanks,
Owen

rokicki · 2007-03-09 18:36

If you don't want them to share the same variable space and pin space, either declare them in separate
subobjects, or declare two instances (either using two declarations or an array). Either way should work.

Mike Green · 2007-03-09 18:40

If you have two instances of FullDuplexSerial either in the same object or declared in different objects or if you have an array of FullDuplexSerial objects, they will not conflict as long as they use different I/O pins. In addition, there will be only one copy of the code although there will be multiple copies of their data (one for each instance). Each instance will run in its own cog. You don't need locks unless one particular instance is potentially called by multiple cogs.

It's difficult to declare objects at one level of the object structure and have them used at another level. If you really have to do it, there's a discussion and examples of the technique posted in this forum. It requires that the setup routine modify some of the byte codes of the compiled program.

Owen · 2007-03-09 21:00

Just so i'm clear on this, if I have full duplex serial running in the toplevel object and running in a seperate object they will use the same copy of code but have seperate variable like creating an array of full duplex serial objects?
thanks for the help

Owen

Paul Baker · 2007-03-09 21:12

Owen said...
Just so i'm clear on this, if I have full duplex serial running in the toplevel object and running in a seperate object they will use the same copy of code but have seperate variable like creating an array of full duplex serial objects?
thanks for the help

Owen

Correct

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Mike Green · 2007-03-09 21:12

Owen,
That's correct.

Stan671 · 2007-03-10 00:25

Interesting ... I am trying to get my mind around this.

In my current project - a three wheeled holonomic robot - I need to control three motors simultanously using a PID speed control algorithm.· I invision a wheel control method that constantly reads a specific memory location that contrains the desired speed and makes sure the motor stays at that speed.· I would then load three "copies" of this method into three cogs to just run all by themselves without any need for the main routine to worry about them.· The main routine just stores the desired speeds into the memory locations and the wheels magically respond.

So, can someone give me skeleton code or draw me a diagram to show the relationships between the methods so that I have one copy of the wheel control method running with three sets of variables.

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Stan Dobrowski

T Chap · 2007-03-10 01:00

Stan, here are some snippets of an idea that might work. Each method has it's local variables that it works with, but the local variables are initialized and updated via the radr(record address) which is the key to one method spread over multi cogs.


VAR
   long X, Xcurrent, EnaX
   long Y, Ycurrent, EnaY
   long Z, Zcurrent, EnaZ

PUB Start
   cognew(moveX, @stack0)
   cognew(moveY, @stack1)
   cognew(moveZ, @stack2)

PUB moveX
   motor(2, @X, 1, 0, 18)

PUB moveY
   motor(0, @Y, 1, 0,  10)

PUB moveZ
   motor(4, @Z, 1, 0,  22)

PUB Motor(pinstart, radr, forward, reverse, enab) | mstep, mdir, pos, rvrs, accel, decel, arate, run, ,Ena
   Mstep := pinstart
   Mdir := pinstart + 1
   for := foward
   revs := reverse
   mEna := Ena
   repeat
      outa[noparse][[/noparse]mEna] := 1
      frqa := 1
      if LONG[noparse][[/noparse]radr] > LONG[noparse][[/noparse]radr + 4]

Post Edited (originator) : 3/10/2007 1:07:14 AM GMT

Paul Baker · 2007-03-10 01:01

You would declare it as an array in the objects:

OBJ
mctrl[noparse][[/noparse]3] : motor_control

Then use the indice to access methods:

mctrl[noparse][[/noparse]0].start(x,y,z)
mctrl[noparse][[/noparse]1].start(a,b,c)
mctrl[noparse][[/noparse]2].start(m,n,o)

One thing to note about multiple instances, anything placed in the DAT section is common to all instances. This·can be handy if you want them to have a means of doing communication but anything that is volatile and instance specific should be placed in the VAR section.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Post Edited (Paul Baker (Parallax)) : 3/10/2007 7:58:17 AM GMT

T Chap · 2007-03-10 07:03

*There is an intentional " " before the indice for posting purposes only

Main Program:

VAR

OBJ  
    mtr[noparse][[/noparse] 3]   :  "mtrTestObjectLower"

PUB Start
  cognew(mtr1, @stack0)
  cognew(mtr1, @stack1)
  cognew(mtr1, @stack2)

PUB mtr1
   mtr[noparse][[/noparse] 0].start(13)

PUB mtr2
   mtr[noparse][[/noparse] 1].start(14)

PUB mtr3
   mtr[noparse][[/noparse] 2].start(15)

Motor object:


VAR
    LONG  X

PUB Start(pin)
    x := pin
    dir[noparse][[/noparse]x] := 1
    repeat
        outa[noparse][[/noparse]x] := 1
        waitcnt(cnt + 80_000_000)
        outa[noparse][[/noparse]x] := 0
        waitcnt(cnt + 80_000_000)

This is a very cool discovery! Thanks Paul!

Post Edited (originator) : 3/10/2007 8:51:36 AM GMT

Paul Baker · 2007-03-10 08:00

Unfortunately the Quick reply interprets [noparse][[/noparse]#] as font size #, please note I have changed the line in the previous post to mctrl[noparse][[/noparse]3] : motor_control

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Post Edited (Paul Baker (Parallax)) : 3/10/2007 8:10:48 AM GMT

Paul Baker · 2007-03-10 08:10

Correct, to get concurrent action you need you use a cognew/coginit [noparse]:)[/noparse]

Also you need to change the following line:

····mtr[noparse][[/noparse]3]···:··"mtrTestObjectLower"

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Stan671 · 2007-03-10 20:44

Paul & Originator: Thank you·for the code examples.· I will study them and try them out in order to understand them.· Great information - Thanks.

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Stan Dobrowski

Paul Rowntree · 2007-03-12 02:09

Greetings All;
I notice that the above coding follows a slightly different style from that provided in the Prop manual (Chapter 3, p134-136), in which the Start routine in the Motor object would do the cognew call, using a local definition of the stack in a VAR block. This frees the main driving module from having to know too much about the innards of the cogged code, eliminates having to define separate stacks for each instance, and to my mind makes cleaner code.

Is this just a style question, or are there any practical implications, one way or the other?
Cheers!

Paul Rowntree

multiple instances of object in an object

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