Can the SX generate a 32 bit word?

datacps

I read the information on the DDS that uses a 32 bit word command to generate a frequency from 0 to 30 mhz. I also got info that the prop chip can do it but I don't know assembly or Spin.· I have my circuit working perfectly Thanks to Bean with a freqout up top 20Khz with 1 hz accuracy of 1 hz.· The um-fpu chip is 14.00 dollars just to write 32 bit words. Then another 14 for the DDS chip.. I also was wondering what is the highest freqout possible (it does not have to be accurate above 20khz.) It just needs to send a high freqout to pulse a neon transformer and light up a tube. I was testing one and I set my Function generator to 271khz to light the tube I was using.·I did my·PCB layout to include both chips and a fram chip too incase I need to go that route...·I am trying to figure out which way to go on this?

Also the EEPROMs are 2.40 @ I rather buy another sxchip 28 or 48 for 2.51 and get 50 million times better chip.
·

Sparks-R-Fun

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

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

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

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

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

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

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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www.hittconsulting.com


Post Edited (Bean (Hitt Consulting)) : 8/7/2007 12:59:51 PM GMT

datacps

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..