Can the SX generate a 32 bit word?

Comments

• Sparks-R-Fun Posts: 388

  2007-08-01 16:33 edited 2007-08-01 16:33

  The SX uses an 8-bit core. Internally all math and logic operations are done using 8-bit numbers. Larger numbers can be “processed” through the use of additional instructions and logic. SX/B adds this additional processing whenever Word variables are used instead of Byte variables. So the answer to your question is that the SX can generate a 32-bit number if you explicitely program it to do this. However it can not natively do this with a built-in instruction.
  
  You may want to look at the 32-bit math routines found on SxList.com If you want to learn to do 32-bit math on the SX you can save $14.00 - $2.51 = $11.49. If you think it will take you more than an hour or two to set that up and want to save time… $14 might not seem so steep!
  
  I can not speak with authority on the maximum frequency limitation of the SX. However, I expect it will be in the MHz range when coupled with an appropriate oscillator. It should be more than enough to drive your neon transformer.
  
  I hope this helps.
  
  - Sparks
• datacps Posts: 139

  2007-08-01 21:43 edited 2007-08-01 21:43

  Thanks Sparks..... I thought it could do it which will save me on getting the CO-Chip. I think I will switch to the SX48 which should have room to do everything I need it to do and I won't have to add another SX 28. I will still use the FRAM chip to store the values that I need to run in automode.
  BTW Sparks you have a great website with a lot of fun stuff. Thanks for all your help.
• Sparks-R-Fun Posts: 388

  2007-08-03 21:18 edited 2007-08-03 21:18

  The SX48 should be able to process your 32-bit numbers fine if you are willing to take the time to figure out how to do it.
  
  As for the website, I assume you are referring to SparkFun.com. I agree. It is a great site! Unfortunately I had no part in that and am not affiliated with the site. I have noticed, however, that a good formula for success in the hobby world is to give information away for free and charge reasonable prices for your products. Parallax and SparkFun both do a great job of this!
  
  Let us know if you get 32-bit math working. I am sure there will be others interested in doing 32-bit math at some point.
  
  - Sparks
• datacps Posts: 139

  2007-08-04 16:30 edited 2007-08-04 16:30

  Thanks again Sparks.. I am reading the information on the SX/List I am trying to figure out how to convert the value from my encoders to a 32 bit. In the examples it show how to add and multiply ect.. I have my sub already readiing my encoders then generating the freqout. I have to look at it and see if there is anyway to convert to 32 bit or I have to change my sub to create the 32 bit value. I am out of RAM so I have to go to the SX/48. I am ordering the SX/48 board for ten dollars.. You can't beat that .. and you are right about how Parallax and Sparkfun. If it where not for the Stamp I would have never got into this hobby and if it wasn't for this forum and the members here like yourself I would have never been able to complete my projects. I am just upset I did not get into it sooner because it is so much fun that I am addicted to it. This is way better than video games.. AS for the MATH it is not my best subject so it will take me a little time to figure it out. I also have to figure a way to store the 32 bit value to the FRAM chip and then run them in a autorun mode. I am open to suggestions...Thanks again
• Peter Verkaik Posts: 3,956

  2007-08-05 18:42 edited 2007-08-05 18:42

  If you want to do 32bit math easily, check out C4SX:
  http://forums.parallax.com/showthread.php?p=663042
  The cc1b compiler supports 32bit integer, fixed point and floating point math.
  It uses operator overloading so you can use the normal expression symbols
  * + - / % (eg. float c = a * b[noparse];)[/noparse].
  
  regards peter
• datacps Posts: 139

  2007-08-07 00:40 edited 2007-08-07 00:40

  I looked at the link but I like using SX/B for now. I will try to do it in SX/B if possible I don't know how I will do it yet. It looks like I will have to eventually learn assembly, or C or another language to do more complicated programming. There should be a way to do it with SX/B I was hoping someone pointed me in the right direction......Thanks for the info Peter.
• Bean Posts: 8,129

  2007-08-07 12:54 edited 2007-08-07 12:54

  Carlos,
  · Here is a routine you can add to the program I already wrote for you that will set the frequency to 8 times the value given. It is a modified version of the original subroutine. You can have both in your program.
  
  · This SetFreqX8 works up to 388KHz (by specifying a value of 48500).
  
  

   
  SUB SetFreqX8  ' SetFreqX8 SUB 1,2
    ' NOTE: Values above 48500 will be limited to 48500 (388 Khz)
    ' NOTE: Values below 70 will not generate anything (no interrupts), 
    '  this can be used to disable the interrupts to do serial comm or other critical timing
   
    IF __PARAMCNT = 1 THEN
      freqWanted = __PARAM1
    ELSE
      freqWanted = __WPARAM12
    ENDIF
   
    IF freqWanted < 70 THEN
      freqWanted = 0
    ENDIF
   
    IF freqWanted > 48500 THEN
      freqWanted = 48500
    ENDIF
   
    tempW2 = $2FAF ' $2FAF0800 = 800,000,000 ((50MHz / 16) * 256)
    tempW = $0800
   
    period = 0
    optReg = 0 ' Assume freq is below 382 (no interrupts)
   
    IF freqWanted > 70 THEN
      optReg = 1 ' Assume prescaler is 1:1
      ' Adjust prescaler to keep frequency above 12207
      DO
        IF freqWanted < 12208 THEN
          freqWanted = freqWanted << 1 ' * 2
          INC optReg ' Adjust prescaler
        ENDIF
      LOOP UNTIL freqWanted >= 12208
    
    
      ' Perform division period = 800,000,000 / frequency
      FOR temp = 1 TO 17
        period = period << 1
        IF tempW2 >= freqWanted THEN
          period.0 = 1
          tempW2 = tempW2 - freqWanted
        ENDIF
        tempW2 = tempW2 << 1
        tempW2.0 = tempW.15
        tempW = tempW << 1
     NEXT
  
   
    ENDIF ' freqWanted >= 382
   
    ' Set period+1
    periodMSBPlus1 = period_MSB + 1
  
   
    ' Get option register value
    LOOKUP optReg, $A0, $88, $80, $81, $82, $83, $84, $85, $86, $87, optReg
  
   
    ' Set option register
    OPTION = optReg
  
   
    ' If no frequency output, make sure pin is low
    IF optReg = $A0 THEN
      FreqOutPin = 0
    ENDIF
  ENDSUB
   
  

  
  Bean.
  
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  Student: I don't know and I don't care
  Teacher: Correct !
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  Post Edited (Bean (Hitt Consulting)) : 8/7/2007 12:59:51 PM GMT
• datacps Posts: 139

  2007-08-08 02:08 edited 2007-08-08 02:08

  Wow Bean thanks again. You make it seems so easy. I would of tried to change the entire Sub. It just needed your touch to a few lines and there it is. This chip and Parallax just keep amazing me. When I think I have to go to a bigger chip or another chip people like yourself have solutions for newbies and others on this forum.
  
  The code for 32 bit
  DO
  IF freqWanted < 12208 THEN
  freqWanted = freqWanted << 1 ' * 2
  INC optReg ' Adjust prescaler
  ENDIF
  LOOP UNTIL freqWanted >= 12208
  
  Original code
  DO
  IF freqWanted > 24414 THEN
  freqWanted = freqWanted >> 1 ' / 2
  DEC optReg ' Adjust prescaler
  ENDIF
  LOOP UNTIL freqWanted <= 24414
  
  With just a few lines of code you can do it just like that.. I was reading all the other stuff and did not have a clue where to begin. I am out of Ram but you just changed a few lines of the original code and it now generates 32 bit. I don't think I can find the words to thank you bean and the other great members on this site.. I am not sure enough to explain what you did but it looks like you multiplied the freqwanted by 2 and inc the adjust prescale .
  new code
  IF freqWanted > 70 THEN
  optReg = 1 ' Assume prescaler is 1:1
  ' Adjust prescaler to keep frequency above 12207
  
  original code
  IF freqWanted >= 382 THEN
  optReg = 4 ' Assume prescaler is 1:8
  
  I posted what I see and hope that maybe this will help other members that may have the same question..