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um-fpu coprocessor — Parallax Forums

um-fpu coprocessor

SawmillerSawmiller Posts: 276
edited 2006-01-27 22:00 in General Discussion
hi there all,
got the um-fpu floating point coprocessor to do some number crunching with my sx-48, and cant seem to get the right numbers back out..
anyone used these b4 ?
i've got it hooked up via I2C.... should i use spi ?

still working on it , but thought i'd drop a question here, will be good to know someone has done it b4 with sxb
dan

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-01-25 22:42
    I've only used it with the BS2, and then I used SPI. Had no problems though, so one would think you could do it with SX/B.

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    Jon Williams
    Applications Engineer, Parallax
  • SawmillerSawmiller Posts: 276
    edited 2006-01-25 23:42
    thanks john.

    rewired it for SPI, looks good now,dont know why it didnt want to do I2C

    but now i have a numbercruncher [noparse]:)[/noparse]

    dan
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-01-26 15:37
    I am a bit curious. Parallax seems to get a lot of people that want to use the um-fpu for Astronomy.

    Are you using it for that? And if the answer is 'yes', will you be integrating your calculatons with a real-time clock?

    It seems everytime someone has an Astronomy project, they merely focus on the number crunching, but it they are really going to apply this robotically to control the movement of a telescope it seems that they have to sync the calculation iterations to a time period.

    Having an autonomous clock may compensate for delays or other glitches.

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    Post Edited (Kramer) : 1/27/2006 3:20:25 PM GMT
  • SawmillerSawmiller Posts: 276
    edited 2006-01-26 17:04
    no, im interfacing a magnostrictive linear position sensor, and since its a word value and i want to be able to have it position a moving head in realtime after doing the calculation for converting inches to position.. ie i want the head to drop 9/16 " for a 1/2" board starting with a 20"· high block of wood...... save me figuing out that stuff

    there is a addon mod that i could get for the sawmill that does the job, but its $1500 and since the sawmill is a hobby now, and i have manufactured hydraulic componets for it, i thought i would just play with making this componet....

    so far i have got it to work with the sensor, and with the UM-FPU using spi ( still having trouble with some of the functions ) now i'm going back and doing the keypad to enable me to enter commands

    precision with that sensor is like 2200 counts ( roughly) for 24 inches, right now im using to the 1/16th of a inch, could go to 1/32 but the mill doesnt need that precision yet.. using the timer on the sx48 btw..

    anyways,· thats what im playing with currently, just got in the ic2/uart eval board and musing on it tongue.gif

    dan
  • BeanBean Posts: 8,129
    edited 2006-01-27 03:15
    Dan,
    Would you mind posting your code ? I'd love to see it.
    Bean.

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    ·
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-01-27 15:32
    Having been a carpenter and home builder, 1/32nd precision is excellent.
    Anything more is unneeded as wood shrinks and expands with humidity. Even at 1/32nd, the wood must not be green in order to take advantage of such.

    I assume this is rough cut, rather than trying to get a smooth surface. That is usually provided by a planer.

    Post the project too, if you care to share. I lived in Eugene, Oregon for 15 years and originally there were 20 saw mills of a wide variety. These days, only two remain.

    A small mobile mill can go into the forest and really achieve a lot. You can mill all the lumber for a rural home on site and then just build it in a few months.

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    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
  • dkemppaidkemppai Posts: 315
    edited 2006-01-27 18:30
    Kramer said...
    Having been a carpenter and home builder, 1/32nd precision is excellent.
    Anything more is unneeded as wood shrinks and expands with humidity. Even at 1/32nd, the wood must not be green in order to take advantage of such.



    Yeah, it's tough to get tight tolerances with wet wood. Espically if there are any internal stresses
    in the tree. (I've seen some boards bend 6 inches over 8 feet when cutting wet lumber)

    However, once the wood is properly dried and the good stuff is selected and planed, a 1/32 is a mile!
    At least for furnature work, anyway. FYI, the lift for my router has 1/512th inch resolution!·(And it repeats to that!) Also it·is not unusual to use a·micrometer 1/1000th for measurements of stock thickness. However, shrinkage and expansion due to moisture change can be .020 in/in from winter to summer.

    Wood is·a fun change from MCU's...·· ...At least·you can·sand off bits that don't fit.·I'd like to see
    someone sand off the extra bits in an MCU!

    -Dan

    ·
  • SawmillerSawmiller Posts: 276
    edited 2006-01-27 22:00
    LOL

    on 12 hour nights right now so no time for experimenting, but heres the original code, without the Um-fpu, in it you can see where i am integrating the keypad... its a 2x 8 matrix so it will be a lowprofile box

    its unfinished, but the code parts for the linear sensor using the timer and outputing to the lcd work right now

    dan
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