REading a value from a Cog???

SailerMan

Basically I have code to Read a Sony REmote running in an endless loop in a cog ....Call it Cog#0.

I want another cog#1 to be·notifyed that data has been recieved in·Cog#0·and what that data is.

Is there a way to do this?

Thanks,
Eric

PS any people in Pennsylvania out there?

·

James Long

Eric,

There are multiple ways to do this......depends on if you want to go through the hub or not.

1. Direct method (real fast).......If you have a extra pin you are not using. Make it an output and set it high when the data is ready. You main loop can look at the pin and retreive the data when the pin goes high.

2. If you can't go with that option. Make a byte VAR. Slice it up into 8 bit flags. byte[noparse][[/noparse]0] through byte[noparse][[/noparse]7] and you can set those flags high....and have the main loop see if the bit is high or low. When the bit is high retreive the data.

The data passing is a little different.

Main loop (cog#1)

mypassedinformation *8 /2

Data loop (cog #0)

long[noparse][[/noparse]mypassedinformation] = what ever data to be passed····· (the size can be byte,word,long,)



You can thank Beau, Paul, Mike and a few other to get this through my thick skull.

Hope this helps,

James L

SailerMan

I think I understand what you are saying.
I will try when I get home and ask questions where needed.

mypassedinformation *8 /2

Is anything specific with the line above?



Thanks for your help,

Eric

James Long

Is anything specific with the line above? said...
(replace this text with what was said)

No....just that you use the information there.

James L

SailerMan

I am planning on making the IR Code an Object...Will I declare (mypassedinformation) in the VAR Block of the IR Object or the Main Program.

Like I said I can't test this out yet.. I'm just thinking.

SailerMan

I have tried everything I know, which isn't to much... [noparse]:)[/noparse] to get this to work.

I created a SonyIRDecoder Spin Object.

It basically runs in a loop waiting for IR data to come.

When Data arrives it is decoded into Device ID and Button Code.

In my Main program I use the object like normal

IR : "SonyIRDecoder"
 
Pub Main
   IR.Start(24)
   Repeat
    ------------I want to see the Device ID and Button Code Variables here...

How Do I get access to these? I tried the info below but could not get it to work.

Regards,

Eric

Paul Baker

To communicate data between objects you must pass thier location be reference. So when you call IR.Start it will have two arguments, the pin assignment and the location of the variables. The code within your SonyIRDecoder uses the pointer to the base address of the variable block passed to it to assign the data a value which can then be read by the master object.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

acantostega

Hi,
I'm sure this has been addressed before in the forums, so you might want to struggle with the seach engine to find some of those threads
One approach I recall is to have your IR object communicate with other cogs through a shared variable. Say you want to share the value in the variable "Info". Then have your IR object something like:

'IRthingie code
Var
   long myInfoAddress

PUB start(InfoAddress)
  myInfoAddress := InfoAddress ' copy address of info variable
  ' then start infinite loop in a separate cog as usual

in which you pass the address of a variable, probably a global variable in your "main" code. So from your main code you do something like:

' "Main" code
Var 
   byte Info 'or word, long
Obj
   IRthingie : "IRThingie"
PUB start
   IRthingie.start(@Info) ' pass address of info to IR object

The IR object would update the Info variable in the code running as an endless loop in the separate cog, like so:

' IRThingie code
newvalue := ... 'some routine to get new value
byte[noparse][[/noparse]myInfoAddress]:= newvalue ' update Info variable, use byte[noparse][[/noparse]] to dereference myInfoAddress

The "client", perhaps the "main" thread (which instantiated the IRthingie object) will periodically consult the Info variable as usual:

' Main code
if (info == something)
   doSomething()
' etc

To ensure the data in info is "fresh", you might set it to an "illegal" value (e.g. -1) from your "main" code after reading it, and then poll info until it takes a value different from -1.
I haven't taken into account concurrency problems. If you just update a 32-bit or less variable, there'll be no problem because read/write operations on these are atomic. If it's not the case, you can use semaphores or a buffer approach.
Warning: I haven't tested this code and it might have mistakes. There also might be a better way, I'm mainly translating from a C mental model. I'm sure Mike Green has explained this better somewhere

SailerMan

It's all working now... thanks for the help... I'm learning new things every day. [noparse]:)[/noparse]

Best Regards,
Eric