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EddieB
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PostPosted: Fri Aug 18, 2006 12:18 am 
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Mike, If I read it right you are using the command variable as a semaphore between the interrupt handler and the main loop. When a command is received by the irpd it puts the value in the command variable. Once you see in the main loop that the command variable has been updated you act on it and then reset it.
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Robot Dude
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PostPosted: Fri Aug 18, 2006 12:19 am 
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SN96 wrote:
Note: I went back and made some quick changes to the code. Sorry...

>>>Edit
This wait is killing me, Jim.... Are you done yet?.... :shock:

Sorry, I made the changes and although it does work, it's still having the same problems. I think it's in the interupt code. Or how I'm trying to wrap basic around it. :(

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SN96
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PostPosted: Fri Aug 18, 2006 12:25 am 
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Robot Dude wrote:
SN96 wrote:
Note: I went back and made some quick changes to the code. Sorry...

>>>Edit
This wait is killing me, Jim.... Are you done yet?.... :shock:

Sorry, I made the changes and although it does work, it's still having the same problems. I think it's in the interupt code. Or how I'm trying to wrap basic around it. :(


I was kidding about the wait comment. :lol:

I figured there was something more to the problem then what meets the eye. I gave it my best shot though. :lol:

So some how with the interupt, varables are getting jumbled up I guess. Acidtech is the best person to provide an answer.

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EddieB
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PostPosted: Fri Aug 18, 2006 12:30 am 
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is there a way to block the interrupt while you are accessing the command variable? or force the code to always load the variable from memory every time it is accessed? there is a problem with optimized and compiled languages where a frequently used variable might be held in a register for a few operations rather than pulled from memory every time it is needed. If an interrupt is changing the contents of that variable at the same time though the main loop won't see the change and could possible overwrite it. In C/C++ there is a storage class called volatile that is specifically to address this problem. I don't know if the basic stuff you are using has that same type of issue, but if it does there may be a similar fix to the problem.
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Robot Dude
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PostPosted: Fri Aug 18, 2006 12:34 am 
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SN96 wrote:
I figured there was something more to the problem then what meets the eye. I gave it my best shot though. :lol:

So some how with the interupt, varables are getting jumbled up I guess. Acidtech is the best person to provide an answer.


I forgot to mention that a reset brings it back to life for a little while, so I think it's the interupt code that is causing it to act up.

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Last edited by Robot Dude on Fri Aug 18, 2006 12:36 am, edited 1 time in total.

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SN96
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PostPosted: Fri Aug 18, 2006 12:34 am 
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You know Eddie, I think you might be on to something! :lol:

In both Pbasic and Mbasic, you can write variables to the eeprom. This might be a good thing to try. This could help "protect" the variable from being affected from the interrupt.

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SN96
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PostPosted: Fri Aug 18, 2006 12:37 am 
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Robot Dude wrote:
SN96 wrote:
I figured there was something more to the problem then what meets the eye. I gave it my best shot though. :lol:

So some how with the interupt, varables are getting jumbled up I guess. Acidtech is the best person to provide an answer.


I forgot to mention that a reset brings it back to life, so I think it's the interupt code that is causing it to act up.


What about what Eddie said about writing the variables to eeprom, could this possibly help?

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Robot Dude
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PostPosted: Fri Aug 18, 2006 12:37 am 
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SN96 wrote:
You know Eddie, I think you might be on to something! :lol:

In both Pbasic and Mbasic, you can write variables to the eeprom. This might be a good thing to try. This could help "protect" the variable from being affected from the interrupt.


I am currently experimenting with the enable and disable commands. They allow you to enable and disable the interupt. Nothing good to say yet, but I am still working.

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Robot Dude
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PostPosted: Fri Aug 18, 2006 12:46 am 
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I tried disabling the interupt when the decisions are being made.

Code:
main
disable WKPINT_3
   if(command<>0xFF)then
'      serout S_OUT,i115200,["Address = ",hex address,13,"Command = ",hex command,13]

   if (command = 0) then
      servop = 4000
   endif
   if (command = 1) then
      servop = 3000
   endif
   if (command = 2) then
      servop = 2000
   endif
      Command=0xFF
   endif
enable WKPINT_3   

pulsout 15,servop
pause 20

   goto main

But it's still loosing interest in behaving after a while.

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robodude666
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PostPosted: Fri Aug 18, 2006 12:49 am 
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Have you tried mine? Instead of having it send the servo pulse to the servo, make it print it to the terminal. I think its a better method of debugging. You might also want to stick a print into the label which checks for the command.

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Robot Dude
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PostPosted: Fri Aug 18, 2006 1:24 am 
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robodude666 wrote:
Have you tried mine? Instead of having it send the servo pulse to the servo, make it print it to the terminal. I think its a better method of debugging. You might also want to stick a print into the label which checks for the command.

Well I didn't think this was worth trying as it worked fine before I added the pulsout commands. However I did go back and put the terminal serial command back in. Low and behold it is getting corrupt. After working for a while it starts sending garbage to the screen...

At first it works...
Code:
Address = 1
Command = 1
Address = 1
Command = 1


Then after a while it sends this...
Code:
{Ønd = 0
Addresÿî = 0
Comý{Ønd = 0
{Ønd = 0
Addre^þ0
Com
/Ï{ö^þ0
Addre^þ0
Com
/Ï{ö^þ0
Addresÿî = 0
Comý{Ønd = 0
Addresÿî = 0
Comss{Ønd = 0
Addresÿî = 0
Comî = 0


Clicking dissconnect and then reconnect seems to fix it. But it's just temporary...

This is with no pulsout commands. Thanks for making me go back to the beginning. :D

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Last edited by Robot Dude on Fri Aug 18, 2006 1:27 am, edited 1 time in total.

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SN96
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PostPosted: Fri Aug 18, 2006 1:27 am 
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Robot Dude wrote:
So it has to be the interupt code. This is with no pulsout commands. Thanks for making me go back to the beginning. :D


LOL, but it's not all bad though, it's interesting to "see" what was going on... :lol:

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Last edited by SN96 on Fri Aug 18, 2006 1:28 am, edited 1 time in total.

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robodude666
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PostPosted: Fri Aug 18, 2006 1:27 am 
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Yup, thought so. Nothing wrong with your servop stuff, had to be the commands/address it was getting.

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Acidtech
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PostPosted: Fri Sep 08, 2006 1:52 pm 
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It's gona be a little longer before I can get back to this code. But until then...

The problem causing the data to become invalid is being caused because the IRPD is missing a pulse. When it does there is no recovering with the current code because it has no way of knowing it missed a pulse. What needs to be done is setup a TimerA interrupt that keeps track of the current pulse width. By keeping track of the time, if the pulse gets longer than a valid pulse(ie greater than 195) the sequence needs to be reset(setting lasttime = -1 will reset the sequence for the next valid pulse train from the remote).

So here's the code(not tested and probably has bugs/typos):

Code:
ONINTERRUPT WKPINT_3,handle_irpd
ONINTERRUPT TIMERA_OVF,handle_timera
PMR5.bit3 = 1
TMA=4   ;increments on clock/256
ENABLE WKPINT_3
ENABLE TIMERA_OVF

lasttime var long
currenttime var long
datacount var byte
irpd_data var word
command var byte
address var byte
ServoP var word

currenttime=0
lasttime = -1   ;indicate next data should be a startpulse
low 15

main

pulsout 15,servop
pause 20

   if(command<>0xFF)then
;      serout S_OUT,i115200,["Address = ",hex address,13,"Command = ",hex command,13]

      if (command = 0) then
         servop = 4000
      endif
      if (command = 1) then
         servop = 3000
      endif
      if (command = 2) then
         servop = 2000
      endif

      Command=0xFF
   endif
   goto main

;Modified handle_irpd routine
handle_irpd
   if(lasttime<0)then
      datacount=0
      lasttime=currenttime+TCA
   else
      datacount=datacount+1
      lasttime=(currenttime+TCA)-lasttime
      irpd_data=irpd_data>>1       
      if(lasttime>175 AND lasttime<195)then
         irpd_data=0
      elseif(lasttime>100 and lasttime<120)
         irpd_data.bit10=1
      elseif(lasttime>65 and lasttime<85)
         irpd_data.bit10=0
      else
         ;invalid pulse received
         lasttime=-1   
         resume   ;resume imediately   
      endif
      if(datacount=12)then
         lasttime=-1
         command = irpd_data&0x7F
         address = irpd_data>>7
      else
         lasttime = currenttime+TCA
      endif
   endif   
   resume

handle_timera
   currenttime=currenttime+256
   resume


That should work to handle bad pulses. I may have the wrong name for the TIMERA_OVF interrupt but the rest looks right.

Nathan
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Robot Dude
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PostPosted: Mon Oct 30, 2006 4:16 pm 
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I moved this to the Bipeds section.

http://www.lynxmotion.net/viewtopic.php?t=1242

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