How do you recycle VAR I need to free up some RAM in a Basic Stamp (Resloved)

sam_sam_sam

Hi EveryOne

This is a project that I have been ·ask to do·by employer

As of right now I can not give all of the details.......................
................·but when the Project is done I will share with all of you on the Forum


I know that I have·This a another Post but this is a different question
http://forums.parallax.com/showthread.php?p=804156

http://forums.parallax.com/showthread.php?p=804554



▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
··Thanks for any··that you may have and all of your time finding them

·
·
·
·
Sam

Post Edited (sam_sam_sam) : 8/5/2009 2:09:55 AM GMT

W9GFO

VAR word workVal


Use workVal in all your routines where the value does not need to be saved. Even when it does need to be saved you can copy it.

importantValue = workVal

Aside from optimizing your code or using a different Stamp, I don't know what else you could do.

Rich H

sam_sam_sam

VAR word workVal········ ·'This will not compile am i missing something in what you have here

importantValue = workVal

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
··Thanks for any··that you may have and all of your time finding them

·
·
·
·
Sam

W9GFO

Oops! It should be;

workVal VAR word

Rich H

phil kenny

Zoot helped me with this same topic.

See

http://forums.parallax.com/showthread.php?p=696777

phil

sam_sam_sam

phil

Thank For sharing that post link

Time···· ·VAR· ·WORD
S_Time·· VAR·· Time

There is one thing about using this is that

1·· You have to have them neat to each other or you get an error need a·label· for one of them ·S_Time or Time
··· ·I can not remember which gave the error

2 You can only use this if that VAR is not need in two places at one time

This will work if let say that you want to set a CON on the fly and use a switch to set the CON· and you go back to you main routine then this will
work

Time· VAR used in one place then you want use the S_Time VAR two command line down from the first one
·· I found out the Hard Way· this dose not work

·It also warn you about this in the on-line help




▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
··Thanks for any··that you may have and all of your time finding them

·
·
·
·
Sam

Post Edited (sam_sam_sam) : 8/5/2009 2:18:15 AM GMT

phil kenny

Hello Sam,

Perhaps I mislead you. You can't free up RAM in the BS2. The use
of aliasing (giving the same memory location two names) is of more
use with the multi-slot Stamps such as BS2P, BS2x, and BS2Pe.

Zoot was trying to demonstrate two things:

1) create a Byte array named Time

2) Using an alias to access the first byte in that array:

' here is another common example for timekeeping bytes -- 
' you can access individual elements by name, or write to the array:

time VAR Byte(10)
secs VAR time  ' alias to first "element", aka time(0)

The variable Time must be defined first. The alias secs does not have
to be defined next. It may be defined anywhere later in the code.

Multi-slot Stamps have much more program space, but they still have
only 26 bytes of RAM. However, they also have a scratchpad memory
which can be used to gain space for your variables, but the process
isn't straight forward.

Tracy Allen has an excellent discussion of how to make use of the
scratchpad memory at:

www.emesystems.com/BS2SX.htm

phil

sam_sam_sam

' {$STAMP BS2}
' {$PBASIC 2.5}
'Sand_Silo_Test_Demo
RC              PIN     15
' -----[noparse][[/noparse] Var ]-------------------------------------------------------
 

PD              VAR     Word
RC_Set          VAR     PD
SL              VAR     Word
Seconds         VAR     Word
 
secs            VAR     Byte
mins            VAR     Byte
hrs             VAR     Byte
J               VAR     Byte
N               VAR     Word
B               VAR     N
D               VAR     Word
F               VAR     Word
x               VAR     Word
'RC_Set          VAR     Word

RC_Diff         CON     600
RC_Max          CON     613
RC_Min          CON     13
 

 DO
 
 IF IN0 = 0 THEN set
 
 IF SL = 50000 THEN EXIT
 

'DEBUG CLS
DEBUG HOME, DEC RC_Set, TAB, "1.", DEC3 X, CLREOL, CR,
           "PD", DEC5  PD, CR, "SL", DEC5  SL, CR, "B", DEC5  B, CR,
            DEC5 ? seconds, CR, DEC2 ? secs, CR, DEC2 ? mins, CR, DEC2 ? hrs, CR
 
 
seconds  = seconds + 1
secs = secs + 1
 
SL = seconds + (seconds ** X)    ' x = a value some thing like 28626 that done with the SET routine   
PD = Seconds  + (seconds ** X)       
B = seconds + (seconds ** 28626)
 
IF secs = 60 THEN
 Secs = 00
 Mins = Mins + 1
 
 IF Mins = 60 THEN
 Mins = 00
 Hrs = Hrs + 1
 
 ENDIF
 ENDIF
 
LOOP
 
END

set:
 
RC_Set = PD
B = N
 
DO WHILE IN0 = 0

    Main:
    HIGH RC                                            ' charge the cap
    PAUSE 1                                            ' for 1 ms
    RCTIME RC, 1, RC_SET                               ' measure RC discharge time
    PAUSE 50
 
 N = RC_set - RC_min MAX RC_diff  ' binary division loop
 D = RC_diff
 
 
 
FOR J=15 TO 0               ' 16 bits
N=N//D<<1                   ' remainder*2
F.BIT0(J)=N/D               ' next bit
 
NEXT
 
 DEBUG HOME, DEC RC_Set, TAB, "1.", DEC3 X, CLREOL

 x = f ** 1000
 
  LOOP

  RETURN

In my case I have a routine that has two routine one routine runs when the switch =·1
the other runs when the swich·= 0

This allow me·to set a value that is need in the main routine

This is not·ALL of the code routines and not all of the VAR are listed in this Demo code and as you can see that these two·routines use this much RAM··the SET·routine ·take 5 WORDs and 1 BYTE


To add the SET routine with the compled code routine that I am using it put me 3 WORDs over so now what am I going·to do is reuse some VAR
that are not need in the SET routine that are only need in the main routine


▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
··Thanks for any··that you may have and all of your time finding them

·
·
·
·
Sam

Post Edited (sam_sam_sam) : 8/5/2009 3:48:00 AM GMT

W9GFO

You might be able to free up one word if you get rid of the secs and mins variables.

You can divide seconds by 60, if no remainder then one minute has passed. Same with dividing by 3600, then one hour has passed.

It looks like PD is the same as SL which is the same as RC_set

Does X always equal f ** 1000, if so, you don't need x.

It seems really difficult to me to try to reduce you VAR space without knowing how those VARs are used in other parts of your code.

Rich H

Tracy Allen

The following rewrite of the set routine dispenses with several of the variables that need not be kept (N, D, F). At the end it saves the multiplier x as DATA, so that it can "stick" after a restart or power cycling. All the variables used in the set routine, except x are free again after the set routine finishes. Note that your program does a "GOTO set", but the set routine has a RETURN at the end. Use GOSUB instead of GOTO.

PD  VAR Word    <---- reusing these two variables temporarily, alias name them if it makes you feel better
x  VAR Word
J   VAR Nib   <---- note J only has to be a NIB
X0ee  DATA Word 28626
RC_Max          CON     613
RC_Min          CON     13
RC_Diff         CON    RCmax - RCmin   <---- define this in terms of the two other constants that come from testing the adjustment range


set:
  DO 
    HIGH RC                                            ' charge the cap
    PAUSE 1                                            ' for 1 ms
    RCTIME RC, 1, PD                             ' measure RC discharge time
    HIGH RC
    DEBUG HOME, DEC PD, TAB  <---- show this value now, going on to change PD
 
     PD = PD - RC_min MAX RC_diff  ' Make sure PD falls within range of the CONstants
 ' ---- binary division loop ----
    FOR J=15 TO 0               ' 16 bits   NOTE:  J only needs to be a NIB
      PD=PD//RC_diff<<1                   ' remainder*2 <--- note the divisor is constant, PD dividend is reduced directly
      x.BIT0(J)=PC/RC_diff               ' next bit   <- using x for the quotient
     NEXT
 
     DEBUG DEC x, TAB, "1.", DEC3 x** 1000, CLREOL, CR  ' <--- show ** multiplier and decimal equivalent
  LOOP WHILE IN0 = 0
  READ X0ee, Word PD   ' <--- now using PD for the old multiplier
  IF PD <> x THEN WRITE X0ee, Word x  ' <--- write new multiplier if it is different from old
  RETURN

The main code should start off, when in0=1, with a READ of x,

READ x0ee, Word x   ' <---- x multiplier value is stored in eeprom from calibration set step

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Tracy Allen
www.emesystems.com

sam_sam_sam

Tracy Allen

·Reusing·these·two·variables·temporarily,·alias·name·them·if·it·makes·you·feel·better
I would feel better if I used· alias·name·it would be easyer for to know what VAR ·I am using and what it is·for
·I did think about just using what VAR not being used at that with out changing the name


Thanks for sharing this the way you have this help me·understand more about what is happing when


···PD·=·PD·-·RC_min·MAX·RC_diff·················································· '·Make·sure·PD·falls·within·range·of·the·CONstants
··················································· '·----·binary·division·loop·----
····FOR·J=15·TO·0····································································· ·'·16·bits···NOTE:··J·only·needs·to·be·a·NIB
······PD=PD//RC_diff<<1··························································· · ·'·remainder*2·<---·note·the·divisor·is·constant,·PD·dividend·is·reduced·directly
······x.BIT0(J)=PC/RC_diff·····························································'·next·bit···<-·using·x·for·the·quotient

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
··Thanks for any··that you may have and all of your time finding them

·
·
·
·
Sam

Steph Lindsay

Hi sam_sam_sam,

I'm glad our forum gurus took good care of you! Just FYI for others who read this post:

Two techniques to save variable space are introduced in the Stamps in Class text Applied Robotics with the SumoBot·(a free download). One is·the use of a multipurpose·"temp" variable, and the other is the use of a single byte·variable as a flag register·to quickly·evaluate and act upon the state of·6 sensors.

Have fun,

-Steph Lindsay

Editor, Parallax Inc.